splicing molex connectors

J

JC

Guest
Hey.

What's everybody's opinion on my splicing a couple of device power
cables onto one of the lines that comes out of my 300-W power supply, so
as to let me have up to 5-6 IDE devices (with added controller, of
course; my power supply has only 4 + FDD). It'd look something like
this, below. I know that I can buy the connectors, but I did this on a
Friday night after the new hardware arrived and wonder if I can keep it.
I've secured the splice with twist ties.

Thanks,

jc

Power Supply
------------------------------------
/ \
/ \
/ \
| |
| |
| |
Splice -> /| |
/ | _ | _
/ | / \ | / \
/ | / \ | / \
/ |/ \ |/ \
| |---| |---| |---| |---|
| | | | | | | | |
| |___| |___| |___| |___|
|
|
|
|
|
| _
| / \
| / \
|/ \
|---| |---|
| | | |
|___| |___|
 
<< Hey.

What's everybody's opinion on my splicing a couple of device power
cables onto one of the lines that comes out of my 300-W power supply, so
as to let me have up to 5-6 IDE devices (with added controller, of
course; my power supply has only 4 + FDD). It'd look something like
this, below. I know that I can buy the connectors, but I did this on a
Friday night after the new hardware arrived and wonder if I can keep it.
I've secured the splice with twist ties.

Thanks,

jc >>

Personally, I think it was a waste of time. They sell power splitters that
split 1 drive power connection into 2. Would've saved you lots of time.
 
make sure the power supply is rated to handle the extra load.



"JC" <gymus@yahoo.com> wrote in message
news:adDJb.11984$qS3.527@nwrdny03.gnilink.net...
Hey.

What's everybody's opinion on my splicing a couple of device power
cables onto one of the lines that comes out of my 300-W power supply, so
as to let me have up to 5-6 IDE devices (with added controller, of
course; my power supply has only 4 + FDD). It'd look something like
this, below. I know that I can buy the connectors, but I did this on a
Friday night after the new hardware arrived and wonder if I can keep it.
I've secured the splice with twist ties.

Thanks,

jc

Power Supply
------------------------------------
/ \
/ \
/ \
| |
| |
| |
Splice -> /| |
/ | _ | _
/ | / \ | / \
/ | / \ | / \
/ |/ \ |/ \
| |---| |---| |---| |---|
| | | | | | | | |
| |___| |___| |___| |___|
|
|
|
|
|
| _
| / \
| / \
|/ \
|---| |---|
| | | |
|___| |___|
Click to expand...
 
Don't splice the connectors. For a few dollars you can buy power splitters.
I have used a lot of these.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"JC" <gymus@yahoo.com> wrote in message
news:adDJb.11984$qS3.527@nwrdny03.gnilink.net...
Hey.

What's everybody's opinion on my splicing a couple of device power
cables onto one of the lines that comes out of my 300-W power supply, so
as to let me have up to 5-6 IDE devices (with added controller, of
course; my power supply has only 4 + FDD). It'd look something like
this, below. I know that I can buy the connectors, but I did this on a
Friday night after the new hardware arrived and wonder if I can keep it.
I've secured the splice with twist ties.

Thanks,

jc

Power Supply
------------------------------------
/ \
/ \
/ \
| |
| |
| |
Splice -> /| |
/ | _ | _
/ | / \ | / \
/ | / \ | / \
/ |/ \ |/ \
| |---| |---| |---| |---|
| | | | | | | | |
| |___| |___| |___| |___|
|
|
|
|
|
| _
| / \
| / \
|/ \
|---| |---|
| | | |
|___| |___|
 
JC wrote:

Hey.

What's everybody's opinion on my splicing a couple of device power
cables onto one of the lines that comes out of my 300-W power supply, so
as to let me have up to 5-6 IDE devices (with added controller, of
course; my power supply has only 4 + FDD). It'd look something like
this, below. I know that I can buy the connectors, but I did this on a
Friday night after the new hardware arrived and wonder if I can keep it.
I've secured the splice with twist ties.

Thanks,

jc

Power Supply
------------------------------------
/ \
/ \
/ \
| |
| |
| |
Splice -> /| |
/ | _ | _
/ | / \ | / \
/ | / \ | / \
/ |/ \ |/ \
| |---| |---| |---| |---|
| | | | | | | | |
| |___| |___| |___| |___|
|
|
|
|
|
| _
| / \
| / \
|/ \
|---| |---|
| | | |
|___| |___|
Click to expand...
Instead of splicing, you could just get an adapter designed for just
that purpose.

But if you don't want to buy one, then go ahead and splice. Just make
certain that you make your connections good, and don't put too many
devices onto one line coming off the power supply. Adding 2 connectors
shouldn't be a problem if you have a power supply of sufficient size to
handle all devices.
 
"Jerry G." <jerryg50@hotmail.com> writes:

Don't splice the connectors. For a few dollars you can buy power splitters.
I have used a lot of these.
Click to expand...
Just double check that they are wired correctly! I've heard of factory
new splitters with +5 and +12 reversed. This of course does bad things.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: The email address in this message header may no longer work. To
contact me, please use the feedback form on the S.E.R FAQ Web sites.
 
On 03 Jan 2004 18:54:41 GMT quadrajet1@aol.com (Quadrajet1) wrote:

What's everybody's opinion on my splicing a couple of device power
cables onto one of the lines that comes out of my 300-W power supply, so
as to let me have up to 5-6 IDE devices (with added controller, of
course; my power supply has only 4 + FDD).
I've secured the splice with twist ties.

Personally, I think it was a waste of time. They sell power splitters that
split 1 drive power connection into 2. Would've saved you lots of time.
Click to expand...
I have added output power lines to several PC power supplies over the
years, for exactly the same reasons. In my case, I opened the PS and
found that the PC board inside had many more wire holes than were
used. I just soldered the new ones directly into the board.

I realize that one can add splitters (the price varies) but that can
double the current thru one of those molex connectors, and I don't
know how close they are to their current ratings. It also adds
compound voltage drops on a single wire, which might cause problems in
some hardware.

Off hand, I'd guess that my way was the most reliable, which was part
of the reason I picked it. The splice method would be my second
choice, as long as the splice was done well. And the splitter would be
the least reliable.

OTOH, I've never heard of any such reliability problems like these
actually occurring, so maybe it's a complete red herring. This might
give the advantage to the splitters if you can get them for cheap.

The first time I did mine, I actually went out to buy splitters, but I
needed 3 and the place I went to wanted $10 apiece for them. When I
asked if they had any dead PSs, they gave me one for free and I
scavenged the extra wires from it for nothing. Yes, I spent a lot more
time, but it cost me nothing and I think I got a super end result.

-
-----------------------------------------------
Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------
 
Jim Adney wrote:

On 03 Jan 2004 18:54:41 GMT quadrajet1@aol.com (Quadrajet1) wrote:


What's everybody's opinion on my splicing a couple of device power
cables onto one of the lines that comes out of my 300-W power supply, so
as to let me have up to 5-6 IDE devices (with added controller, of
course; my power supply has only 4 + FDD).
I've secured the splice with twist ties.


Personally, I think it was a waste of time. They sell power splitters that
split 1 drive power connection into 2. Would've saved you lots of time.


I have added output power lines to several PC power supplies over the
years, for exactly the same reasons. In my case, I opened the PS and
found that the PC board inside had many more wire holes than were
used. I just soldered the new ones directly into the board.

I realize that one can add splitters (the price varies) but that can
double the current thru one of those molex connectors, and I don't
know how close they are to their current ratings. It also adds
compound voltage drops on a single wire, which might cause problems in
some hardware.

Off hand, I'd guess that my way was the most reliable, which was part
of the reason I picked it. The splice method would be my second
choice, as long as the splice was done well. And the splitter would be
the least reliable.

OTOH, I've never heard of any such reliability problems like these
actually occurring, so maybe it's a complete red herring. This might
give the advantage to the splitters if you can get them for cheap.

The first time I did mine, I actually went out to buy splitters, but I
needed 3 and the place I went to wanted $10 apiece for them. When I
asked if they had any dead PSs, they gave me one for free and I
scavenged the extra wires from it for nothing. Yes, I spent a lot more
time, but it cost me nothing and I think I got a super end result.

-
-----------------------------------------------
Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------
Click to expand...
I agree with you completely. The most reliable way was the way that you
did it. by adding more wires to the power supply, you lessened the risk
of overloading the capacity of the existing wiring and connectors. The
only worry is overloading the total capacity of the power supply.

The least reliable of these methods is the splitter, for the very
reasons you specified, plus they tend to come loose at the worst
possible times.
 
"Daniel L. Belton" wrote ...
I agree with you completely. The most reliable way was
the way that you did it.
Click to expand...
NO! NO! NO! DANGER, WILL ROBINSON!!!

by adding more wires to the power supply, you lessened
the risk of overloading the capacity of the existing wiring
and connectors.
Click to expand...
By opening the power supply, you exposed the most hazardous
part of the whole PC. In the (hopefully unlikely) event of the
power supply catching fire, you could lose your fire insurance
if they discover that you messed around inside the PC power
supply enclosure. Even professionals who know what they are
doing avoid this.

A sophisticated switch-mode power supply is NO PLACE
for an amateur to be dinking around. Particularly those that
are designed and mass-produced to the thinnest of safety
margins that they can get away with.

The wires and molex connectors are vastly (10x to 20x or
more) OVERrated. "Overloading" them with conventional
loads like hard drives isn't even a remote possibility.

The only worry is overloading the total capacity of the
power supply.
Click to expand...
The ONLY point on which we can agree.

The least reliable of these methods is the splitter, for
the very reasons you specified, plus they tend to come
loose at the worst possible times.
Click to expand...
The Molex connectors on the splitter adapters are just
as reliable as the ones that are already there on the PS
wiring (and on the back of the drives). I maintain
hundreds of PCs and have NEVER seen a failure of a
Molex connector.

NEVER OPEN THE POWER SUPPLY CASE OF A
COMPUTER UNLESS YOU ARE VERY FAMILIAR
WITH THE HAZARDS AND OPERATION OF SWITCH-
MODE POWER SUPPLIES AND YOU ALSO HAVE A
*VERY GOOD* REASON TO DO SO.

THERE ARE SAFETY HAZARDS TO YOU WHILE
YOU ARE INSIDE THE CASE AS WELL AS POTENTIAL
FOR CREATING ONGOING FIRE/SAFETY HAZARDS
FROM ANY MODIFICATIONS.

Adding connectors for additional drives is not even
remotely a justification for opening a power supply.

Concluding that there is extra capacity because there are
"many more wire holes than were used" on the power
supply circuit board is a clear demonstration of lack of
understanding the electrical and safety issues.
 
Richard Crowley wrote:

"Daniel L. Belton" wrote ...

I agree with you completely. The most reliable way was
the way that you did it.


NO! NO! NO! DANGER, WILL ROBINSON!!!


by adding more wires to the power supply, you lessened
the risk of overloading the capacity of the existing wiring
and connectors.


By opening the power supply, you exposed the most hazardous
part of the whole PC. In the (hopefully unlikely) event of the
power supply catching fire, you could lose your fire insurance
if they discover that you messed around inside the PC power
supply enclosure. Even professionals who know what they are
doing avoid this.

this is a bunch of BS. IF they cancelled fire insurance because of
Click to expand...
this, then every repaired TV, radio, stereo, computer, monitor, etc...
would cause people to lose their insurance. and in my experience over
the past 30 years is that most of the time while I am in a power supply,
I will be able to see problems from the manufacturing that could
possibly cause problems on down the road. And if I see a problem, then
I fix it, making the power supply much safer. and professionals that
know what they are doing would not even hesitate to open up a power supply.

A sophisticated switch-mode power supply is NO PLACE
for an amateur to be dinking around. Particularly those that
are designed and mass-produced to the thinnest of safety
margins that they can get away with.

The wires and molex connectors are vastly (10x to 20x or
more) OVERrated. "Overloading" them with conventional
loads like hard drives isn't even a remote possibility.
Click to expand...
No, the wires and connectors are not over rated. I have found several
supplies straight from the factory that have everything running off of
ONE line coming out of the power supply. I even saw one that had the
+12v wire for the hard drive burned in two after only 5 minutes of
service. Doesn't sound over rated to me, but very much under rated.

The only worry is overloading the total capacity of the
power supply.


The ONLY point on which we can agree.


The least reliable of these methods is the splitter, for
the very reasons you specified, plus they tend to come
loose at the worst possible times.


The Molex connectors on the splitter adapters are just
as reliable as the ones that are already there on the PS
wiring (and on the back of the drives). I maintain
hundreds of PCs and have NEVER seen a failure of a
Molex connector.
Click to expand...
I have several dozen molex connectors here in a box with burned contacts
on them, mainly from bad crimps at the factory.
NEVER OPEN THE POWER SUPPLY CASE OF A
COMPUTER UNLESS YOU ARE VERY FAMILIAR
WITH THE HAZARDS AND OPERATION OF SWITCH-
MODE POWER SUPPLIES AND YOU ALSO HAVE A
*VERY GOOD* REASON TO DO SO.

THERE ARE SAFETY HAZARDS TO YOU WHILE
YOU ARE INSIDE THE CASE AS WELL AS POTENTIAL
FOR CREATING ONGOING FIRE/SAFETY HAZARDS
FROM ANY MODIFICATIONS.

Adding connectors for additional drives is not even
remotely a justification for opening a power supply.

Concluding that there is extra capacity because there are
"many more wire holes than were used" on the power
supply circuit board is a clear demonstration of lack of
understanding the electrical and safety issues.
Click to expand...
I will agree that the "many more holes than were used" is a bad
indicator of power supply capacity. There are many more factors
involved in determining the load versus capacity.

Having been working on PC power supplies for 20 years now, and other
equipment for over 30, I still contend that the safest way is to add
more wires to the power supply as long as it isn't overloading the capacity.
 
<< > By opening the power supply, you exposed the most hazardous
part of the whole PC. In the (hopefully unlikely) event of the
power supply catching fire, you could lose your fire insurance
if they discover that you messed around inside the PC power
supply enclosure. Even professionals who know what they are
doing avoid this.

this is a bunch of BS. IF they cancelled fire insurance because of
Click to expand...
this, then every repaired TV, radio, stereo, computer, monitor, etc...
would cause people to lose their insurance. and in my experience over
the past 30 years is that most of the time while I am in a power supply,
I will be able to see problems from the manufacturing that could
possibly cause problems on down the road. And if I see a problem, then
I fix it, making the power supply much safer. and professionals that
know what they are doing would not even hesitate to open up a power supply. >>

There is a BIG difference in "modifying" an existing power supply and
"repairing" one. I seriously doubt they'd dig that far, but ya never know if
they don't want to pay a claim.
 
"Daniel L. Belton" wrote ...
this is a bunch of BS. IF they cancelled fire insurance
because of this, then every repaired TV, radio, stereo,
computer, monitor, etc... would cause people to lose
their insurance.
Click to expand...
Remember that this newsgroup is read by many (mostly)
amateurs with NO experience in the hazards of switchmode
power supplies. It is highly irresponsible to assume that
everyone has the same experience level that you do. You
apparently haven't dealt with an insurance adjuster yet.

No, the wires and connectors are not over rated. I have
found several supplies straight from the factory that have
everything running off of ONE line coming out of the power
supply. I even saw one that had the +12v wire for the hard
drive burned in two after only 5 minutes of service. Doesn't
sound over rated to me, but very much under rated.
Click to expand...
You cite a infinitessimal fraction of all the power supply
cables out there running right now as you are reading this.
If they were NOT over-rated, then we would be seeing a
large number of failures. Go and look up the current capacity
of those wire gages and then come back and tell us that they
are not over rated. Can't believe that someone with "30
years of experience" has never seen a wire current capacity
chart (or actually looked up the ratings of Molex pins.)

Having been working on PC power supplies for 20 years
now, and other equipment for over 30, I still contend that
the safest way is to add more wires to the power supply as
long as it isn't overloading the capacity.
Click to expand...
Not only do you have a provably wrong theory, but it is also
highly irresponsible to purvey it in this forum to amateurs
that barely know which end of a soldering iron to grasp.
 
Quadrajet1 wrote:

By opening the power supply, you exposed the most hazardous

part of the whole PC. In the (hopefully unlikely) event of the
power supply catching fire, you could lose your fire insurance
if they discover that you messed around inside the PC power
supply enclosure. Even professionals who know what they are
doing avoid this.


this is a bunch of BS. IF they cancelled fire insurance because of
this, then every repaired TV, radio, stereo, computer, monitor, etc...
would cause people to lose their insurance. and in my experience over
the past 30 years is that most of the time while I am in a power supply,
I will be able to see problems from the manufacturing that could
possibly cause problems on down the road. And if I see a problem, then
I fix it, making the power supply much safer. and professionals that
know what they are doing would not even hesitate to open up a power supply.

There is a BIG difference in "modifying" an existing power supply and
"repairing" one. I seriously doubt they'd dig that far, but ya never know if
they don't want to pay a claim.
Click to expand...

I agree that modifying one is much different than repairing one, but in
this case it would still be much safer than overloading the existing
wiring and connectors. Adding more would be safer as long as you did
not add so much that you overload the capacity of the power supply.
Also, most power supplies have built in fusing that will blow if
overloaded before burning anything up.
 
On Sun, 4 Jan 2004 19:34:40 -0800 "Richard Crowley"
<rcrowley7@xprt.net> wrote:

"Daniel L. Belton" wrote ...
I agree with you completely. The most reliable way was
the way that you did it.

NO! NO! NO! DANGER, WILL ROBINSON!!!
Click to expand...
Sounds a bit like Chicken Little....

by adding more wires to the power supply, you lessened
the risk of overloading the capacity of the existing wiring
and connectors.

By opening the power supply, you exposed the most hazardous
part of the whole PC.
Click to expand...
That's true, but I deal with much more dangerous things every day.
That doesn't mean that they shouldn't be done, but it does mean that
they need to be done carefully.

A sophisticated switch-mode power supply is NO PLACE
for an amateur to be dinking around.
Click to expand...
In my book, the real amateurs out there are those who believe that
nothing can be fixed unless you've been factory certified. In the
cases where I've done this monstrously dangerous and risky task you
obviously abhore, I've also taken the opportunity to fix up the
incredibly poor soldering job that the factory did.

My impression is that the vast majority of people posting here are
serious, knowledgable people with good electronic backgrounds.
Certainly we get occasiional posts where the questions make it clear
that they really have no idea what they are talking about.

The wires and molex connectors are vastly (10x to 20x or
more) OVERrated. "Overloading" them with conventional
loads like hard drives isn't even a remote possibility.
Click to expand...
Certainly a possibility. What about when you have 3-4 hard drives
powered thru a single Molex? Are you still so certain?

The only worry is overloading the total capacity of the
power supply.
Click to expand...
No question about it. Agreed

NEVER OPEN THE POWER SUPPLY CASE OF A
COMPUTER UNLESS YOU ARE VERY FAMILIAR
WITH THE HAZARDS AND OPERATION OF SWITCH-
MODE POWER SUPPLIES AND YOU ALSO HAVE A
*VERY GOOD* REASON TO DO SO.
Click to expand...
As alarmist as this looks, I agree with it. I feel the same way about
car doors and bicycle handlebars. Almost everything we do requires
some thought to keep us on the safe side of things. There are some
people who shouldn't do anything. There are others who could be
trusted with almost anything. Blanket statements like the alarmist
ones here really don't help.

THERE ARE SAFETY HAZARDS TO YOU WHILE
YOU ARE INSIDE THE CASE AS WELL AS POTENTIAL
FOR CREATING ONGOING FIRE/SAFETY HAZARDS
FROM ANY MODIFICATIONS.
Click to expand...
Did you really think that this would come as a surprise to anyone?

I just wonder, with this kind of viewpoint, have you ever done any of
the following:

Drive a car?
Fix a radio, TV, or VCR?
Added an outlet or wiring in your home?
Replaced brake pads on your car?
Trimmed your own shrubs?
Mowed a lawn; sharpened a lawnmower blade?
Fixed a flat on a car or bike?
Welded or brazed a support structure for something that weighed more
than 100 lbs?

Each of these tasks, if done wrong, can be life threatening. For each
of these tasks, there are professionals who are trained to do them.

In fact, I've got to wonder why, with a point of view like this, you
would even want to consider reading a newsgroup that included the word
repair in its name.

Concluding that there is extra capacity because there are
"many more wire holes than were used" on the power
supply circuit board is a clear demonstration of lack of
understanding the electrical and safety issues.
Click to expand...
No one here made such a statement. Clearly this would be illogical,
just as illogical as adding extra connectors by means of splitters
under the same assumption.

-
-----------------------------------------------
Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------
 
<<
I agree that modifying one is much different than repairing one, but in
this case it would still be much safer than overloading the existing
wiring and connectors. Adding more would be safer as long as you did
not add so much that you overload the capacity of the power supply.
Also, most power supplies have built in fusing that will blow if
overloaded before burning anything up.
I have to agree 100%. But from an insurance claim standpoint, they can say
you modified it, and with the plug in Y-splitters, at least you can blame the
manufactures of those things. Good luck finding who they are of course.

A good analogy is the overloaded wall socket. It would be a bad idea to
change out the socket for a larger multiple socket, and NOT upgrade the wire,
but if you overload it with extension cords, heaters, etc... Either way you're
risking chaos.
 
"Daniel L. Belton" wrote
I agree that modifying one is much different than repairing
one, but in this case it would still be much safer than
overloading the existing wiring and connectors.
Click to expand...
To help you out, here is the very first wire capacity chart from a
Google search: http://www.powerstream.com/Wire_Size.htm

It shows that an 18-gauge wire (much SMALLER than anything
I have EVER seen in the cheapest and sleaziest PC power supply)
is rated at 16 AMPS. And to quote the description from that web
page: "The Maximum Amps for Power Transmission uses the 700
circular mils per amp rule, which is very very conservative."

16 amps is enough to "very very conservatively" simultaneously
START eight Hitachi 180GB hard drives (note that they actually
RUN at a fraction of that current). Reference:
http://www.hgst.com/hdd/support/d180gxp/d180gxp.htm
(I used the worst-case startup current of the 12-volt supply
which runs the motor. The 5-volt supply is a fraction of that.)

Any of you running EIGHT 180Gb hard drives in your
computers? Perhaps not. And remember that this is running
all eight hard drives THROUGH A SINGLE "UNDERSIZE"
WIRE but still with a "very very conservative" margin.

OTOH 14 gauge wire (which I see most commonly in PC
power supplies) is "very very conservatively" rated for
32 amps. That is 16 Hitachi 180Gb drives all starting
simultaneously through a single wire!

And as for the Molex connectors, the capacity of EACH
PIN is 10 AMPS (or limited by the wire capacity). You
would have to create a daisy-chain of 3 or 4 Y-adaptors
to even approach exceeding the capacity of a single pin
(of the four). Reference:
http://www.molex.com/pdm_docs/ps/b9clpatf_ps.pdf
(bottom of page 2).

I have shown with actual manufacturers' data that under
a combination of completely worst-case conditions,
there is no significant danger of "overloading the existing
wire and connectors". You are virtually guaranteed to
overload the power supply before even approaching
the capacity limits of the wires or connectors.
 
Richard Crowley wrote:

"Daniel L. Belton" wrote

I agree that modifying one is much different than repairing
one, but in this case it would still be much safer than
overloading the existing wiring and connectors.


To help you out, here is the very first wire capacity chart from a
Google search: http://www.powerstream.com/Wire_Size.htm
Click to expand...
Ok... using that chart, which is for open air wiring, nit bundled
wiring, a typical 22gauge wire can carry 7 amps. put 4 drives like you
say to do with a splitter, and you have overloaded the wiring... look
at the specs for a typical hard drive... here are the specs for the
Seagate ST410014A, 40GB drive...(the 40 - 200 gb are the same specs
powerwise) 2.8 amps @ +12v +/- 10%... 4x2.8 amps comes out ot be more
that the 7 amps that the wire is rated for.

Congratulations... by your advice of using the splitter, you just
caused an overload condition, and a fire hazard...


It shows that an 18-gauge wire (much SMALLER than anything
I have EVER seen in the cheapest and sleaziest PC power supply)
is rated at 16 AMPS. And to quote the description from that web
page: "The Maximum Amps for Power Transmission uses the 700
circular mils per amp rule, which is very very conservative."
Click to expand...
look at your drive power wiring again... it's not 18 gauge wire...
most use 22 - 20 guage.
16 amps is enough to "very very conservatively" simultaneously
START eight Hitachi 180GB hard drives (note that they actually
RUN at a fraction of that current). Reference:
http://www.hgst.com/hdd/support/d180gxp/d180gxp.htm
(I used the worst-case startup current of the 12-volt supply
which runs the motor. The 5-volt supply is a fraction of that.)

Any of you running EIGHT 180Gb hard drives in your
computers? Perhaps not. And remember that this is running
all eight hard drives THROUGH A SINGLE "UNDERSIZE"
WIRE but still with a "very very conservative" margin.
Click to expand...
Actually, I have 10 running here in my computer at home.

OTOH 14 gauge wire (which I see most commonly in PC
power supplies) is "very very conservatively" rated for
32 amps. That is 16 Hitachi 180Gb drives all starting
simultaneously through a single wire!
Click to expand...
14 gauge?? not a chance... 14 gauge is used in the house wiring...
never seen it in the power to a hard drive.
And as for the Molex connectors, the capacity of EACH
PIN is 10 AMPS (or limited by the wire capacity). You
would have to create a daisy-chain of 3 or 4 Y-adaptors
to even approach exceeding the capacity of a single pin
(of the four). Reference:
http://www.molex.com/pdm_docs/ps/b9clpatf_ps.pdf
(bottom of page 2).
Click to expand...
I did state that the molex connectors I saw go bad were due to bad
crimps... but you also must factor in that the current carrying
capacity of the wiring actually goes down when you do put a connector
on. you raise the resistance.
I have shown with actual manufacturers' data that under
a combination of completely worst-case conditions,
there is no significant danger of "overloading the existing
wire and connectors". You are virtually guaranteed to
overload the power supply before even approaching
the capacity limits of the wires or connectors.
Click to expand...
That chart also states that the capacities are under ideal conditions.
and here's a quote from that same chart... "As you might guess, the
rated ampacities are just a rule of thumb. In careful engineering the
insulation temperature limit, thickness, thermal conductivity, and air
convection and temperature should all be taken into account."
 
"Daniel L. Belton" wrote ...
look at your drive power wiring again... it's not 18
gauge wire... most use 22 - 20 guage.

Actually, I have 10 [drives] running here in my
computer at home.
Click to expand...
I see your problem. You are trying to run 10 drives from
a power supply that uses 20-22ga wires!

First, you should consider buying decent power supplies
that don't use tinsel as a substitute for real wire. A quick
check of all the power supplies around the house shows
that the one with the SMALLEST wire is 16ga (rated for
22A.) And that is the one that I removed from a friend's
computer because it failed. But I'm sure that is just a
coincidence(!)

Second, you appear to be trying to kludge a small
power supply to run a "server-class" computer.
If the case holds 10 drives, it should have come with
a power supply that has adequate wiring for 10 drives.
Or, to put it another way, if you are running 10 drives,
you should be using a power supply conservatively
rated (and wired) for 10 drives.

Are you trying to run the power supply up against its
max limits for 12v and 5v? Remember that the mother
board (CPU, etc.) is using *some* of that power. :)

If I had a computer power supply that used 22ga wire
I would be afraid to even turn it on! I'll readily confess
to being more conservative than you. It was considered
good engineering practice since our grandparents' era.

14 gauge?? not a chance... 14 gauge is used in the
house wiring...
Click to expand...
Until your posting, I had never dreamed that anyone
would use 14ga for "house wiring". I've never SEEN
(or installed) anything smaller than 12ga. Perhaps I
live in a part of the USA with more recent wiring
practice.

I did state that the Molex connectors I saw go bad
were due to bad crimps... but you also must factor
in that the current carrying capacity of the wiring
actually goes down when you do put a connector
on. you raise the resistance.
Click to expand...
"25 mOhms max" (0.025 ohms MAXIMUM) op cit

That chart also states that the capacities are under
ideal conditions.
Click to expand...
If you have ever worked on much industrial equipment,
you would realize that the inside of even the warmest
pc box is heaven by comparison. We loose perspective
on reality if we think that computer cases are somehow
tough conditions. We have certainly revealed that we
live in very different worlds.
 
"Quadrajet1" wrote ...
this is a bunch of BS. IF they cancelled fire insurance
because of this, then every repaired TV, radio, stereo,
computer, monitor, etc... would cause people to lose
their insurance.
Click to expand...
Taking something to a "professional" for repair is NOT the
same as hacking it yourself. Even if you know what you are
doing. Haven't dealt with many insurance adjusters, I take it?
I sincerely hope you never have to.
 
"Quadrajet1" wrote ...
this is a bunch of BS. IF they cancelled fire insurance
because of this, then every repaired TV, radio, stereo,
computer, monitor, etc... would cause people to lose
their insurance.

Taking something to a "professional" for repair is NOT the
same as hacking it yourself. Even if you know what you are
doing. Haven't dealt with many insurance adjusters, I take it?
I sincerely hope you never have to.
Click to expand...
Hey, I didn't write that!!!
 
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