short circuit 220 V

[ernio]

I tried to control a bulb (220V, 60w) with a relay (220 V, 10A). The relay was controled with the output (0) of High Power 18-pin Project Board (5V DC). It worked witn leds (5V DC) but when I put the bulb (220V AC) it produces a short circuit tha switch off the ligth at home.
Is it sure to work with Picaxe, a relay and 220 V? or Is there something I don't understand?
Thanks

 

[kevrus]

Hi Ernio,
Could you post a picture/drawing of how you've wired everything?
You could have the relay contact wired across the L and N causing a dead short upon energising the relay (if you pcked the N/O contact) Using a N/C contact would cause a short immediately upon turning on the 220v supply.
Difficult to be more specific without more info really

 

[Michael 2727]

I hope there is one thing you do understand ?, 220V can Kill You !

Sounds more like a short or incorrect wiring in the Relay side of things.

Just wondering how much experience you have, maybe call in a friend or qualified
person who actually knows what is going on to help you

I can see the sequel to the "Three Little Pigs" story in the making - "The Four little Pigs"
This is where the geeky cousin comes to visit and Burns The House Down.

 

[ernio]

I'm using a relay Finder 40.52. in a protoboard . The first two pins (5V), one to the output 0 in the protoboard and the other to ground. I have used the two rearest pins to conect one wire of the bulb. Sorry, I can't get goog pictures. Thanks for your time

Hi Ernio,
Could you post a picture/drawing of how you've wired everything?
You could have the relay contact wired across the L and N causing a dead short upon energising the relay (if you pcked the N/O contact) Using a N/C contact would cause a short immediately upon turning on the 220v supply.
Difficult to be more specific without more info really

 

[kevrus]

Michael is right to point out the dangers.
It takes very little current flowing through a person to be fatal...approx 50mA I believe is all that is required affect the heart (ventricular fibrulation...but DrAcula would be able to confirm), hence the 30mA rating of RCDs and RCBOs for protection against electrocution.

 

[Andrew Cowan]

To control a light, you should have neutral always connected, and switch live. This equals no danger of short circuit.

Can we see a photo?

A

 

[Michael 2727]

Check there is no solder bridging on the PCB with the relay socket.

 

[hippy]

Before ever connecting something which switches mains to the live mains make sure you have fully tested and proven its functionality. This sounds to me like a wiring mistake and wiring mistakes can kill. If they don't kill they can dump mains into the PICAXE circuit and into the PC and destroy that. If you are dead you probably will not care about your smouldering PC and all the lost data, but if you are alive you might.

Three golden rules of developing circuits with mains -

1) Always use a suitable circuit / earth leakage breaker.

2) Never work alone.

3) Make sure whoever is with you is trained in resuscitation techniques and knows exactly what to do in the event of electrocution.

 

[moxhamj]

Thanks for the heads-up kevrus. Yes, a few milliamps of AC mains can kill.

I've been stressing for the last hour because I saw this post but then someone came in with a heart attack so I haven't been able to reply.

Please don't go any further with this mains project. If you are blowing the fuse you are building circuits that could put your life in danger. If your toaster blew the fuse you would put it in the bin - please consider doing the same with this project, and then starting again with a safer option.

If you don't have a photo or a schematic we can't debug it, but there are a few possibilities. The relay might not be mains rated and might have fused. You might have read the pinout upside down (looking at the pins from the bottom or looking from the top - which is the correct circuit?). You might have a solder blob on the protoboard. You might have a stray strand of wire shorting across.

If you want 60W of light then there is a very simple solution - use a car headlamp. They are 12V at 5A which is 60W and are available at any service station or car accessory store. Light is light, whether it comes out of a mains bulb or a 12V bulb. But 12V is much safer. It is also more convenient - you can use a relay or a mosfet.

Please don't use mains - we are talkng about your life here.

 

[boriz]

Ditto. And..

Just the fact that you would ask a question like that is all I need to know.

Either you know what you are doing with mains electricity, or you are taking your life into your own hands. And possibly someone else’s. You’re playing with fire, and I’m not going to help you do it.

 

[ernio]

Thank you. The idea of car headlamp is very useful.
Reading more about relays and the necessity of isolation, I've noticed that perhaps a solid state relay could be the solution
Thanks again

Thanks for the heads-up kevrus. Yes, a few milliamps of AC mains can kill.

I've been stressing for the last hour because I saw this post but then someone came in with a heart attack so I haven't been able to reply.

Please don't go any further with this mains project. If you are blowing the fuse you are building circuits that could put your life in danger. If your toaster blew the fuse you would put it in the bin - please consider doing the same with this project, and then starting again with a safer option.

If you don't have a photo or a schematic we can't debug it, but there are a few possibilities. The relay might not be mains rated and might have fused. You might have read the pinout upside down (looking at the pins from the bottom or looking from the top - which is the correct circuit?). You might have a solder blob on the protoboard. You might have a stray strand of wire shorting across.

If you want 60W of light then there is a very simple solution - use a car headlamp. They are 12V at 5A which is 60W and are available at any service station or car accessory store. Light is light, whether it comes out of a mains bulb or a 12V bulb. But 12V is much safer. It is also more convenient - you can use a relay or a mosfet.

Please don't use mains - we are talkng about your life here.

 

[BeanieBots]

Thank you. The idea of car headlamp is very useful.
Reading more about relays and the necessity of isolation, I've noticed that perhaps a solid state relay could be the solution
Thanks again

STOP THIS RIGHT NOW!

Your last post CLEARLY demonstrates that you don't know what you are doing.
A solid state relay offers no more isolation than a mechanical one.
No matter how good the isolation, it is only isolated if you wire it correctly.
Get somebody to explain things in person before you kill yourself.

I'm fully qualified to work on much higher potentials and I would NEVER consider having mains voltage on a protoboard under ANY circumstances.

 

[westaust55]

Effects of Electric Shock

The attached diagram gives an idea on the effect of various levels of alternating current flowing through the body.

 

[BeanieBots]

Interesting to note that the "standard" leakage trip current (~30mA) is right on the far eged of "considerable discomfort".
Talking of which, a few decades ago, I came in contact with 60v DC.
The duration was about 10 to 15 secs. No more than an 'odd' sensation. Hence the long duration. Did not occur that the line was live.
About an hour later ABSOLUTE AGONY. (hence I still remember).
The pain lasted about 3 weeks. Similar to cramp.
Maybe the good Doc can advise on what might have happened to cause such pain for so long and so long after the event.
Nonethless, let it be a warning that even "lower" voltages can HURT.

 

[boriz]

“Pain is irrelevant” – 7 of 9.

 

[BeanieBots]

Fortunatley, I was NOT assimulated and I DID resist. (in more ways than one!)

 

[kevrus]

Also, with reference to the RCD tripping, at the rated current of 30mA, the device has to operate within 300mS, whereas at 5x30mA, it has to operate no slower than 40mS. These are standard testsfor RCDs.

Shocks from a DC source causes the muscles to contract and remain so, this is often considered more dangerous due to the inability to 'let go' or to be 'thrown back' from the voltage source as is often the case with AC.

 

[westaust55]

RCD circuit breaker standards

Also, with reference to the RCD tripping, at the rated current of 30mA, the device has to operate within 300mS, whereas at 5x30mA, it has to operate no slower than 40mS. These are standard tests for RCDs.

Furthermore, for the 30mA RDC circut breakers intended for protection of people, the standards have a tolerance of +0/-50%.
So in fact the RCD can trip anywhere in the range 15mA to 30mA.

 

[manuka]

Kiwi corner: Compared with Australia, NZ has very liberal mains regulations, but tellingly associated accidents & fatalities are no higher. Perhaps this relates to our mains electrical awareness "education"?

I'm typical of many who will NOT give casual "2nd hand" advice about mains level wiring and circuitry, as even the most trivial misunderstanding (phase colours especially) can be tragic- perhaps years later. Well meaning commentators may even be legally liable.

But you wanted "60W of light"? As compact fluoros give out 5 times the light of a filament lamp, perhaps just use a 12V 12W CFL, which would only draw 1A. Even better may be a high intensity "Lumiled" style white LED- I've a 12V 3W one here that's almost evil in it's brightness, yet it could be simply & safely controlled.

 

[westaust55]

I'm typical of many who will NOT give casual "2nd hand" advice about mains level wiring and circuitry, as even the most trivial misunderstanding (phase colours especially) can be tragic- perhaps years later. Well meaning commentators may even be legally liable.

True.

A recent SIlicon Chip magazine project had an article where a left over piece of the "green and gold" wire from a cord was being used as an active conductor. They were chastised by a reader in the current edition but no visible statement of warning by the magazine. AS/NZS 3000 wiring rules prohibits the use of either green or yellow for any purpose other than earthing.

 

[manuka]

Westaus55: Yikes- glad that wasn't my published blunder! I recall once using a discarded earth wire as a camping clothes line, & even having reservations about that.

 

[moxhamj]

Would a camping clothes line be valid using earth wire if one end was tied to a metal stake in the ground?

Re BB "Talking of which, a few decades ago, I came in contact with 60v DC.
The duration was about 10 to 15 secs. No more than an 'odd' sensation. Hence the long duration. Did not occur that the line was live.
About an hour later ABSOLUTE AGONY. (hence I still remember).
The pain lasted about 3 weeks. Similar to cramp."

The problem with AC is the heart arrythmias it induces. With lightning, the problem is burns and boiliing water essentially exploding nerves and other tissues. With long duration DC I think that might be good old fashioned electrolysis. Except that the electrolysis is occurring in muscles and nerves, and creating free radicals (ions) which will be reacting with everything nearby. The pain would be due to the inflammation caused as the body fixes the damage, and it wouldn't happen straight away, in the same way that whiplash pain after a car accident is often the worst the next day, not the day it happens.

Re mains wiring - my dad let me build a project when I was 14 but the rule was that before I turned it on, I had to get him to check it. And then I had to take the circuit down to my local electronics store and get them to check it too.

I like the suggestion of 12V compact flouros. I avoid mains wiring because, frankly, it scares me, and there always seems to be a low voltage way to solve the problem anyway.

 

[Michael 2727]

Westy's graph is interesting, just wondering how they arrived at the C2, C3 figures ?
I hope they offered the vict Um reasearcher a Bex and a Good Lie Down afterwards

 

[boriz]

"& even having reservations about that."

LOL

 

[boriz]

Did anyone see the Simpsons episode where they went for ‘family therapy’ with Dr Monroe? Each strapped to an electrocution chair and each with buttons in front of them to shock the other family members?

After completely missing the point and spending several minutes almost killing each other (and making Mr Burns very happy about the increased electricity demand), the Doctor eventually manages to unplug the machine, and from a cloud of smoke Marge says “Thank you Doctor. I think we are making real progress.”

 

[Andrew Cowan]

Westaus55: Yikes- glad that wasn't my published blunder! I recall once using a discarded earth wire as a camping clothes line, & even having reservations about that.

Were you passing a current through the wire to heat it, and thus dry the cothes?

A

 

[louisyuikin]

... just to let the forum know about this latest Sparkfun post/tutorial:

''a small relay board to control the power to a normal AC outlet using 5VDC control''


http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=119

Enjoy (with care)

Ly