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Sylvia Else <sylvia@email.invalid> wrote:
On 03-Feb-22 4:47 pm, Sylvia Else wrote:
I bought this Arduino Relay Board.
https://www.dropbox.com/s/emgdcm33190unse/ArduinoRelayBoard.jpg?dl=0
It\'s about 33mm by 20mm.
The mains contacts are on the left, the control contacts on the right.
What bothers me is the trace from one of the control contacts that runs
across the isolation barrier, near to the mains contacts. It runs to a
diode, from which another traces runs back to the right.
The packaging carries a CE label, but I find it difficult to believe
that this is actually safe.
Sylvia.
I decided to sacrifice the relay itself to examine its construction:
https://www.dropbox.com/s/ly8wlfnkvpl1ea9/c_relay.jpg?dl=0
If the coil wire were to break off its pin there, it could get horribly
close to the mains connected (brass?) plate.
And? The cheapest of relays are cheapy made. If you need safety look up
intrinsically safe relays, and no don\'t then try buy buy fakes ones from
amazon or alibaba.
I salvaged four of these from my dead UPS:
https://au.element14.com/omron/g2r-1-e-12dc/relay-spdt-250vac-30vdc-16a/dp/9949410?st=g2r-1
They\'ve clearly been designed so that there\'s no credible failure mode
that would connect the load to the coil.
Sylvia.
Let me guess, one Omron relay costs the same as 5 chinese house-special relay boards.
I don\'t know about the law where you live, but where I am, products are
required to be safe, and the requirement is not relaxed just because the
product is cheap.
Sylvia Else wrote:
I don\'t know about the law where you live, but where I am, products are
required to be safe, and the requirement is not relaxed just because the
product is cheap.
There is nothing intrinsically unsafe about the relay nor the board
you\'ve posted.
In the case of the relay - copper wire doesn\'t just unwind from a
solenoid bobbin; then there\'s the enamel coating on the wire itself
(breakdown voltage of that being something like 400 - 600 volts, or even
higher).
In the case of the entire assembly, it\'s perfectly fine at the
relatively low voltages and amperages that one can reasonably expect
when playing with an Arduino project. It\'s not like we\'re mucking
around with 100 amps at 240 volts or the like ...
On 07-Feb-22 12:16 pm, Dan Purgert wrote:
Sylvia Else wrote:
I don\'t know about the law where you live, but where I am, products are
required to be safe, and the requirement is not relaxed just because the
product is cheap.
There is nothing intrinsically unsafe about the relay nor the board
you\'ve posted.
In the case of the relay - copper wire doesn\'t just unwind from a
solenoid bobbin; then there\'s the enamel coating on the wire itself
(breakdown voltage of that being something like 400 - 600 volts, or even
higher).
In the case of the entire assembly, it\'s perfectly fine at the
relatively low voltages and amperages that one can reasonably expect
when playing with an Arduino project. It\'s not like we\'re mucking
around with 100 amps at 240 volts or the like ...
This module is sold for controlling household appliances from an
Arduino. Here\'s another vendor\'s description:
https://www.jaycar.com.au/arduino-compatible-5v-relay-board/p/XC4419?pos=2&queryId=a54e7487b5d48b61a328f1327e6d72d7&sort=relevance
Sylvia Else wrote:
I don\'t know about the law where you live, but where I am, products are
required to be safe, and the requirement is not relaxed just because the
product is cheap.
There is nothing intrinsically unsafe about the relay nor the board
you\'ve posted.
In the case of the relay - copper wire doesn\'t just unwind from a
solenoid bobbin; then there\'s the enamel coating on the wire itself
(breakdown voltage of that being something like 400 - 600 volts, or even
higher).
In the case of the entire assembly, it\'s perfectly fine at the
relatively low voltages and amperages that one can reasonably expect
when playing with an Arduino project. It\'s not like we\'re mucking
around with 100 amps at 240 volts or the like ...
This module is sold for controlling household appliances from an
Arduino. Here\'s another vendor\'s description:
Okay, the relay is perfectly safe.
As for the board itself ... google indicates that ~3mm is (or at least
was) the minimum separation on contacts for up to 300V (no distinction
made between AC or DC). I don\'t know if this is current regulation
though.
On 07-Feb-22 5:29 am, Cydrome Leader wrote:
Sylvia Else <sylvia@email.invalid> wrote:
On 03-Feb-22 4:47 pm, Sylvia Else wrote:
I bought this Arduino Relay Board.
https://www.dropbox.com/s/emgdcm33190unse/ArduinoRelayBoard.jpg?dl=0
It\'s about 33mm by 20mm.
The mains contacts are on the left, the control contacts on the right.
What bothers me is the trace from one of the control contacts that runs
across the isolation barrier, near to the mains contacts. It runs to a
diode, from which another traces runs back to the right.
The packaging carries a CE label, but I find it difficult to believe
that this is actually safe.
Sylvia.
I decided to sacrifice the relay itself to examine its construction:
https://www.dropbox.com/s/ly8wlfnkvpl1ea9/c_relay.jpg?dl=0
If the coil wire were to break off its pin there, it could get horribly
close to the mains connected (brass?) plate.
And? The cheapest of relays are cheapy made. If you need safety look up
intrinsically safe relays, and no don\'t then try buy buy fakes ones from
amazon or alibaba.
I salvaged four of these from my dead UPS:
https://au.element14.com/omron/g2r-1-e-12dc/relay-spdt-250vac-30vdc-16a/dp/9949410?st=g2r-1
They\'ve clearly been designed so that there\'s no credible failure mode
that would connect the load to the coil.
Sylvia.
Let me guess, one Omron relay costs the same as 5 chinese house-special relay boards.
I don\'t know about the law where you live, but where I am, products are
required to be safe, and the requirement is not relaxed just because the
product is cheap.
Sylvia.
Sylvia Else <sylvia@email.invalid> wrote:
On 07-Feb-22 5:29 am, Cydrome Leader wrote:
Sylvia Else <sylvia@email.invalid> wrote:
On 03-Feb-22 4:47 pm, Sylvia Else wrote:
I bought this Arduino Relay Board.
https://www.dropbox.com/s/emgdcm33190unse/ArduinoRelayBoard.jpg?dl=0
It\'s about 33mm by 20mm.
The mains contacts are on the left, the control contacts on the right.
What bothers me is the trace from one of the control contacts that runs
across the isolation barrier, near to the mains contacts. It runs to a
diode, from which another traces runs back to the right.
The packaging carries a CE label, but I find it difficult to believe
that this is actually safe.
Sylvia.
I decided to sacrifice the relay itself to examine its construction:
https://www.dropbox.com/s/ly8wlfnkvpl1ea9/c_relay.jpg?dl=0
If the coil wire were to break off its pin there, it could get horribly
close to the mains connected (brass?) plate.
And? The cheapest of relays are cheapy made. If you need safety look up
intrinsically safe relays, and no don\'t then try buy buy fakes ones from
amazon or alibaba.
I salvaged four of these from my dead UPS:
https://au.element14.com/omron/g2r-1-e-12dc/relay-spdt-250vac-30vdc-16a/dp/9949410?st=g2r-1
They\'ve clearly been designed so that there\'s no credible failure mode
that would connect the load to the coil.
Sylvia.
Let me guess, one Omron relay costs the same as 5 chinese house-special relay boards.
I don\'t know about the law where you live, but where I am, products are
required to be safe, and the requirement is not relaxed just because the
product is cheap.
Sylvia.
Yeah, sure. Don\'t worry about those relay boards they\'re completely safe
and meet all safety specs. The law says so, therefor they do.
torsdag den 3. februar 2022 kl. 12.11.15 UTC+1 skrev Dan Purgert:
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512
Sylvia Else wrote:
What bothers me is the trace from one of the control contacts that runs
across the isolation barrier, near to the mains contacts. It runs to a
diode, from which another traces runs back to the right.
It\'s hard to tell since it\'s just a bottom shot, but given the
positioning, I\'d hazard that\'s the flyback diode for when the coil field
is collapsing.
yes, looks like this one: https://www.amazon.com/Tolako-Arduino-Indicator-Channel-Official/dp/B00VRUAHLE
who ever designed it obviously didn\'t spend much time thinking, because there is no reason for those tracks being routed that close to the output side
I agree, this is misrepresented saying it can control 220VAC loads. The
RELAY is indeed safety rated at 10A @ 250VAC,
The issue then is whether a dangerous voltage from the MAINS SUPPLY can get across the gap from contacts to the coil.
For this, there are two questions:
Is the coil side wiring supply earthed ?
Can a user be in contact with the coil circuitry with no safely earth ?
1000 volt spikes on your power line? I have serious doubts aboutJohn Robertson wrote:
===================
I agree, this is misrepresented saying it can control 220VAC
loads. The RELAY is indeed safety rated at 10A @ 250VAC,
** Means only that it can switch that voltage at that current.
Takes no account of many thousand volt spikes that can occur on
the MAINS supply for a variety of reasons. Such spikes will
possibly bridge the contacts and or the gap between them and the
coil terminations on the bad relay that Sylvia bought. Once the
gap is bridged a vert large current can then flow.
It also takes no account that the coil side may be in direct
contact with a user.
Safety involves the WHOLE set up.
...... Phil
Phil Allison <pallison49@gmail.com> wrote in
news:e35dc0bc-df90-413d-b73c-220bde3f11a7n@googlegroups.com:
John Robertson wrote:
===================
I agree, this is misrepresented saying it can control 220VAC
loads. The RELAY is indeed safety rated at 10A @ 250VAC,
** Means only that it can switch that voltage at that current.
Takes no account of many thousand volt spikes that can occur on
the MAINS supply for a variety of reasons. Such spikes will
possibly bridge the contacts and or the gap between them and the
coil terminations on the bad relay that Sylvia bought. Once the
gap is bridged a vert large current can then flow.
It also takes no account that the coil side may be in direct
contact with a user.
Safety involves the WHOLE set up.
...... Phil
1000 volt spikes on your power line? I have serious doubts about
that claim. Maybe back in the sixties when you thought you knew
electronics or power back then. I\'d bet that was how long ago you
looked and drew that lame conclusion. Nowadays... I seriously doubt
it, and I seriously doubt you have looked at how clean an AC line is in
decades.
1000 volt spikes on your power line?
Maybe back in the sixties when you thought you knew
electronics or power back then. I\'d bet that was how long ago you
looked and drew that lame conclusion. Nowadays... I seriously doubt
it, and I seriously doubt you have looked at how clean an AC line is in
decades.
Is the coil side wiring supply earthed ?
Can a user be in contact with the coil circuitry with no safely earth ?
Even if the coil side power supply is earthed, it still might not be
compliant with safety standards.
If one end of the coil is earthed, it
has to be a protective earth, not just any weedy earth wire,
Even if one terminal of the coil is protectively earthed, if the other
end of the coil goes to the arduino etc. then it is still not compliant.
Both ends of the coil can\'t be protectively earthed if you can turn on
the coil, so at least one end needs to have some mains-rated insulation
from the user in order to be compliant. If the arduino is accessible to
touch then this is no good.
Perhaps, but not thousand volt levels short of a lightning strikeDecadentLinux...@decadence.org wrote:
=============================
1000 volt spikes on your power line?
** Yep - easily.
I have serious doubts about that claim.
** LOL wot a hoot.
Maybe back in the sixties when you thought you knew
electronics or power back then. I\'d bet that was how long ago you
looked and drew that lame conclusion. Nowadays... I seriously
doubt it, and I seriously doubt you have looked at how clean an
AC line is in decades.
** Never seen how many items have varistors across the AC inlet ?
Such spikes can be locally generated, at switch off of an
un-supressed inductive loads. A fluro desk light can do it.
Nearby lightning strikes are the major sourceand that is never
going away.
..... Phil
Dan Purgert wrote:
===============
Sylvia Else wrote:
I don\'t know about the law where you live, but where I am, products are
required to be safe, and the requirement is not relaxed just because the
product is cheap.
There is nothing intrinsically unsafe about the relay nor the board
you\'ve posted.
In the case of the relay - copper wire doesn\'t just unwind from a
solenoid bobbin; then there\'s the enamel coating on the wire itself
(breakdown voltage of that being something like 400 - 600 volts, or even
higher).
In the case of the entire assembly, it\'s perfectly fine at the
relatively low voltages and amperages that one can reasonably expect
when playing with an Arduino project. It\'s not like we\'re mucking
around with 100 amps at 240 volts or the like ...
** Very naive idea.
This module is sold for controlling household appliances from an
Arduino. Here\'s another vendor\'s description:
Okay, the relay is perfectly safe.
** You don\'t know that.
As for the board itself ... google indicates that ~3mm is (or at least
was) the minimum separation on contacts for up to 300V (no distinction
made between AC or DC). I don\'t know if this is current regulation
though.
** Think you know SFA - pal.
Relay contacts for 250VAC open about 1mm in practice.
The DC rating is only 24V for the same relay at similar current - cos DC acrs do not self extinguish.
User safety is a separate matter and has got nothing to do with a device simply working.
The issue then is whether a dangerous voltage from the MAINS SUPPLY can get across the gap from contacts to the coil.
For this, there are two questions:
Is the coil side wiring supply earthed ?
Can a user be in contact with the coil circuitry with no safely earth ?
If no earth, clearance and creepage apply - distances an acr or \"tracking\" could breach some day allowing for some contamination of the PCB or relay itself. This link from Sylvia showed a relay that would likely meet the second condition:
https://au.element14.com/omron/g2r-1-e-12dc/relay-spdt-250vac-30vdc-16a/dp/9949410?st=g2r-1
** FYI smartarse:
\"safety earth = \"protective earth\" !!!
Even if one terminal of the coil is protectively earthed, if the other
end of the coil goes to the arduino etc. then it is still not compliant.
** More bullshit - try reading what I ACTUALLY wrote !!
\" Is the coil side wiring supply earthed ?
Can a user be in contact with the coil circuitry with no safely earth ? \"
Phil Allison wrote:
** FYI smartarse:
\"safety earth = \"protective earth\" !!!
If you meant \"protective earth\" when you said:
** More bullshit - try reading what I ACTUALLY wrote !!
\" Is the coil side wiring supply earthed ?
Can a user be in contact with the coil circuitry with no safely earth ? \"
The circuitry might have a protective earth connected to its 0V rail,
Phil Allison <pallison49@gmail.com> wrote in
news:2c72f9ba-ef89-4c60-88a2-27c29d3ae2e3n@googlegroups.com:
DecadentLinux...@decadence.org wrote:
=============================
1000 volt spikes on your power line?
** Yep - easily.
I have serious doubts about that claim.
** LOL wot a hoot.
Maybe back in the sixties when you thought you knew
electronics or power back then. I\'d bet that was how long ago you
looked and drew that lame conclusion. Nowadays... I seriously
doubt it, and I seriously doubt you have looked at how clean an
AC line is in decades.
** Never seen how many items have varistors across the AC inlet ?
Such spikes can be locally generated, at switch off of an
un-supressed inductive loads. A fluro desk light can do it.
Nearby lightning strikes are the major sourceand that is never
going away.
..... Phil
Perhaps, but not thousand volt levels short of a lightning strike
on a line.
https://www.amazon.com/Tolako-Arduino-Indicator-Channel-Official/dp/B00VRUAHLE
                                Mikek
On 2/8/2022 2:43 PM, DecadentLinuxUserNumeroUno@decadence.org wrote:
Phil Allison <pallison49@gmail.com> wrote in
news:2c72f9ba-ef89-4c60-88a2-27c29d3ae2e3n@googlegroups.com:
DecadentLinux...@decadence.org wrote:
=============================
1000 volt spikes on your power line?
  ** Yep - easily.
I have serious doubts about that claim.
**Â LOLÂ Â wot a hoot.
Maybe back in the sixties when you thought you knew
electronics or power back then. I\'d bet that was how long ago you
looked and drew that lame conclusion. Nowadays... I seriously
doubt it, and I seriously doubt you have looked at how clean an
AC line is in decades.
** Never seen how many items have varistors across the AC inlet ?
 Such spikes can be locally generated, at switch off of an
 un-supressed inductive loads. A fluro desk light can do it.
 Nearby lightning strikes are the major sourceand that is never
 going away.
.....  Phil
  Perhaps, but not thousand volt levels short of a lightning strike
on a line.
I haven\'t read all the other responses, but the Q&A on the Amazon site
has a post about 30Vdc Max, and apparently there is a spec that says that.
\"There is a tough to find data sheet that does spec this unit at a max
of 30vdc. Refer to this link for more info,
http://electronics.stackexchange.com/questions/97721/why-ac-points-on-pcb-are-separated-by-a-hole
There are products that are very similar and rated for 120v ac use.
By sinclair macgregor on June 17, 2016
This module should not be used for 110 ac - it does not have adequate
trace separation and thus is rated for 30vdc max.
By sinclair macgregor on June 16, 2016
The relay is rated for 10 amps. To figure watts, just do the math. Amps
X Voltage = Watts 10A X 120v = 1200 watts. This assumes the design of
the PCB can handle the wattage. Assuming this board is of typical
Chinese quality, all bets are off. Better to use a \'hockey puck\' like an
Opto 22 instead of a mechanical ⦠see more
https://www.amazon.com/Tolako-Arduino-Indicator-Channel-Official/dp/B00VRUAHLE#>
By Amazonian on December 11, 2016
I don\'t know the exact limit, but I use it to turn a server pc off and
on. However I wouldn\'t push it pass 400W.
By Dayron VAliente on June 16, 2016 \"
https://www.amazon.com/Tolako-Arduino-Indicator-Channel-Official/dp/B00VRUAHLE
                                Mikek