Shocks in Kitchen

dararyder

Hey folks,

Wondering if any electricians out there can gimme some advice. Occasionally get little shocks from metal objects in my kitchen like the toaster, inside of the dishwasher, kitchen taps etc. Only happens in the kitchen, nowhere else in the house it seems and it'll happen randomly a few times every week.

Brought in an electrician (who wasn't the brightest spark - excuse the pun) last year to take a look and he said it was likely that the house wasn't earthed properly and charged me a fortune to run cable/pipe out to a rod in the back garden. It hasn't made the blindest bit of difference.

Can anyone perhaps shed any light on what the problem might be? Any information much appreciated. Cheers.

Dara

.G.

Possibly a broken or poorly terminated earth in a kitchen socket circuit. Socket circuit earths are usually used to earth kitchen sinks too.

It needs to be looked at by a registered contractor.

dararyder

Thank you mate. Very helpful.

meath4sam

could well be just a built up of static which depends on type of floor and footwear, so by touching earth you are just discharging your built up charge.would i be rite in saying the more you walk around in the room the bigger the shock and once you get a shock if you touch metal again you wont get a shock until you walk around again?

coylemj

meath4sam wrote: »

could well be just a built up of static which depends on type of floor and footwear, so by touching earth you are just discharging your built up charge.would i be rite in saying the more you walk around in the room the bigger the shock and once you get a shock if you touch metal again you wont get a shock until you walk around again?

That's a good point, it's likely the shock is caused by static travelling from the body into the earth circuit via the appliance which means that the appliance probably is earthed properly.

OP, when this happens in an office environment, it's usually blamed on carpets made from synthetic fabrics which act as insulators, they cause static to build up on people's bodies so the next time they touch a computer terminal, radiator or the like, they get a shock. It also happens a lot in offices because air conditioning reduces the amount of moisture in the air so there is no way for static electricity to drain away, either into the air from the skin (because the air is too dry) or into the floor because of the insulation qualities of the synthetic carpet.

The air in a kitchen wouldn't typically be dry if you have a pot on the hob or if someone has run a tap recently but maybe if there is no activity and someone walks in and touches an appliance, it could happen that they get a shock.

The solution is non-technical: install a few potted plants and water them frequently to increase the amount of moisture in the air, this will allow the static to dissipate harmlessly through the air. Hobnail boots may also help but I think your kitchen floor might suffer!

meercat

superg wrote: »

Possibly a broken or poorly terminated earth in a kitchen socket circuit. Socket circuit earths are usually used to earth kitchen sinks too.

It needs to be looked at by a registered contractor.

op
this is the most relevant reply.........imho

meath4sam

meercat wrote: »

op
this is the most relevant reply.........imho

How would you get a shock from a loose or broken earth earth occasionally. If there is a loose earth or broken earth there still should be 0volts on it,I my be wrong as I'm no expert on the theory side of things. It really sounds like static to me have you had a new floor installed since it started or maybe knew shoes.

brightspark

meath4sam wrote: »

How would you get a shock from a loose or broken earth earth occasionally. If there is a loose earth or broken earth there still should be 0volts on it,I my be wrong as I'm no expert on the theory side of things. It really sounds like static to me have you had a new floor installed since it started or maybe knew shoes.

As you say you are no expert!

OP please get a competent guy to check it out.

You need to make sure everything in the kitchen is correctly earthed.

Inbox

meath4sam wrote: »

How would you get a shock from a loose or broken earth earth occasionally. If there is a loose earth or broken earth there still should be 0volts on it,I my be wrong as I'm no expert on the theory side of things. It really sounds like static to me have you had a new floor installed since it started or maybe knew shoes.

Because the loose earth is coming into contact with one of the live conductors and as a result anything connected to that earth will now be live. And depending on where the earth is broke it may not trip out.

OP get someone out straight away if i were you.

GarIT

Inbox wrote: »

Because the loose earth is coming into contact with one of the live conductors and as a result anything connected to that earth will now be live. And depending on where the earth is broke it may not trip out.

OP get someone out straight away if i were you.

While I agree it should be checked immediately, if the live touched the earth and you touched a metal appliance you'd be dead wouldn't you?

Bruthal

Inbox wrote: »

Because the loose earth is coming into contact with one of the live conductors and as a result anything connected to that earth will now be live. And depending on where the earth is broke it may not trip out.

OP get someone out straight away if i were you.

It would be unusual for a loose earth to come into contact with a live terminal.

Usually problems caused by and showing as voltage on metalwork because of a bad earthing setup, are caused by the bad earth in combination with items having earth faults as well.

Meath4sam actually had a point. A disconnected earth on its own wont usually cause voltage to appear on items. If it did, then any items plugged in with properly earthed frames etc would be tripping RCDs all the time.

It is still worth checking by someone competent, as using a voltmeter is probably still legal for qualified lads:pac:

meath4sam

Inbox wrote: »

Because the loose earth is coming into contact with one of the live conductors and as a result anything connected to that earth will now be live. And depending on where the earth is broke it may not trip out.

OP get someone out straight away if i were you.

I agree get someone to look at it but if it was the above u wouldn't be getting a occasional little shock. You would know all about it and not touch anything in the kitchen again. I'm pretty sure it's static as i have come across it before,but should be checked out.

Bruthal

meath4sam wrote: »

I agree get someone to look at it but if it was the above u wouldn't be getting a occasional little shock. You would know all about it and not touch anything in the kitchen again. I'm pretty sure it's static as i have come across it before,but should be checked out.

If the kitchen sink was live, you may not actually get any shock off it at all if wearing runners/shoes, or even dry socks, contrary to what 99% of the worlds population would believe.

Now if something else earthed was nearby, and both sink and earthed item are touched, then its a fair whack alright.

Static is always a possibility. If there is a little crack off it, or if the shock happens and then doesnt if contact is re-made immediately, then static is the likely culprit.

coylemj

Bruthal wrote: »

if the shock happens and then doesnt if contact is re-made immediately, then static is the likely culprit.

Correct, if the shock effect doesn't repeat the instant you make contact for a second time then it's not live electricity, it's static.

If the shocks only happen in the kitchen and nowhere else in the house then it's hardly a loose connection between the live and earth circuits because you'd be getting shocks off the taps in the bathroom and from other appliances around the house. It sounds like static localised in the kitchen because of the characteristics of the floor.

dararyder

meath4sam wrote: »

could well be just a built up of static which depends on type of floor and footwear, so by touching earth you are just discharging your built up charge.would i be rite in saying the more you walk around in the room the bigger the shock and once you get a shock if you touch metal again you wont get a shock until you walk around again?

Thanks for your reply mate. It seems I can keep getting shocked without walking around. Try to take clothes out of washing machine last night and kept repeatedly getting shocked. Had to take clothes out with a plastic kitchen tongs . Its a ceramic tiled floor.

Really appreciate the feedback all!

Bruthal

dararyder wrote: »

Thanks for your reply mate. It seems I can keep getting shocked without walking around. Try to take clothes out of washing machine last night and kept repeatedly getting shocked. Had to take clothes out with a plastic kitchen tongs . Its a ceramic tiled floor.

Really appreciate the feedback all!

Will need to get it looked at anyway. Sounds like a possible earth fault/bad earthing alright.

Is there a properly working RCD on the socket circuits of the house?

brightspark

dararyder wrote: »

Thanks for your reply mate. It seems I can keep getting shocked without walking around. Try to take clothes out of washing machine last night and kept repeatedly getting shocked. Had to take clothes out with a plastic kitchen tongs . Its a ceramic tiled floor.

Really appreciate the feedback all!

Do you have a voltmeter?

coylemj

dararyder wrote: »

Thanks for your reply mate. It seems I can keep getting shocked without walking around. Try to take clothes out of washing machine last night and kept repeatedly getting shocked. Had to take clothes out with a plastic kitchen tongs . Its a ceramic tiled floor.

Really appreciate the feedback all!

If you keep getting shocked then there is a serious problem, you can't get shocked twice in that short space of time from static because it takes time for static to build up on the body.

The washing machine is earthed through the plug and will draw static electricity from your body but that would only be a one-off experience when taking out the washing. If you get repeated shocks then it's not static, it's something far more sinister, get it checked by a pro ASAP and don't let anyone with bare feet go near any of those appliances in the kitchen.

brightspark

coylemj wrote: »

That's a good point, it's likely the shock is caused by static travelling from the body into the earth circuit via the appliance which means that the appliance probably is earthed properly.

The air in a kitchen wouldn't typically be dry if you have a pot on the hob or if someone has run a tap recently but maybe if there is no activity and someone walks in and touches an appliance, it could happen that they get a shock.

The solution is non-technical: install a few potted plants and water them frequently to increase the amount of moisture in the air, this will allow the static to dissipate harmlessly through the air. Hobnail boots may also help but I think your kitchen floor might suffer!

coylemj wrote: »

If you keep getting shocked then there is a serious problem, you can't get shocked twice in that short space of time from static because it takes time for static to build up on the body.

The washing machine is earthed through the plug and will draw static electricity from your body but that would only be a one-off experience when taking out the washing. If you get repeated shocks then it's not static, it's something far more sinister, get it checked by a pro ASAP and don't let anyone with bare feet go near any of those appliances in the kitchen.

Good to see you have changed your opinion, hopefully the OP didn't spend too much on the potted plants. :rolleyes:

dararyder

Bruthal wrote: »

Will need to get it looked at anyway. Sounds like a possible earth fault/bad earthing alright.

Is there a properly working RCD on the socket circuits of the house?

Cheers for the reply mate. To be honest have no idea what an RCD is so your post and posts of all the other kind souls who've answered this thread all point to one thing - i need to get another pro out and this time need to make sure he's on the ball unlike the last chancer.

Thanks to all who helped. Really appreciate it. What a fantastic place the internet can be when it's used by decent souls. Cheers.

dararyder

brightspark wrote: »

Do you have a voltmeter?

Unfortunately not mate but i'll definitely get a spark out to look at it again this week. Cheers.

coylemj

brightspark wrote: »

Good to see you have changed your opinion, hopefully the OP didn't spend too much on the potted plants. :rolleyes:

Don't blame me for trying, this is how the OP originally described the problem....

dararyder wrote: »

Only happens in the kitchen, nowhere else in the house it seems and it'll happen randomly a few times every week.

Then he tells us that he gets repeated shocks while taking wet clothes out of the washing machine which is describing a completely different problem.

Random shocks from earthed appliances is a sign of static electricity, repeated shocks is a sign of an appliance that's live and dangerous.

brightspark

dararyder wrote: »

Unfortunately not mate but i'll definitely get a spark out to look at it again this week. Cheers.

If you can, unplug the washing machine at the very least, and anything else you can avoid using, something in your kitchen is dangerous. If you can't access the plug without pulling out the machine turn off the power at the main board first, don't pull out the machine with the power still on it.

Also try to avoid grabbing anything metal, touch the back of your hand against it first, that way if you get a shock you will be thrown away, instead of grabbing on tighter!

Are your sockets protected by an RCD?

If not you should really consider getting your board upgraded.

Also ask your electrician to check if the equipotential bonding is ok, especially in your kitchen, if he finds problems there it could also be a good idea to check the bathroom and heating systems etc.

The new earth rod etc was probably needed anyway.


I learnt a long time ago not to assume static was causing shocks without eliminating all the alternatives first.

kramer1

Maybe not neutralised and a poorly installed earth rod

mikeoneill893

kramer1 wrote: »

Maybe not neutralised and a poorly installed earth rod

was a common enough problem

fuses and direct earthing on old installations-go figure:cool:


maybe it's just a problem with a local circuit here

SpaceTime

dararyder wrote: »

Thanks for your reply mate. It seems I can keep getting shocked without walking around. Try to take clothes out of washing machine last night and kept repeatedly getting shocked. Had to take clothes out with a plastic kitchen tongs . Its a ceramic tiled floor.

Really appreciate the feedback all!

That is really serious!

Stop using appliances and turn off the mains at the fusebox main switch and get an electrician!

The next shock could be fatal!

Bruthal

SpaceTime wrote: »

That is really serious!

Stop using appliances and turn off the mains at the fusebox main switch and get an electrician!

The next shock could be fatal!

Why,,, is he barely surviving these "shocks"?

knipex

superg wrote: »

Possibly a broken or poorly terminated earth in a kitchen socket circuit. Socket circuit earths are usually used to earth kitchen sinks too.

It needs to be looked at by a registered contractor.

Surely if this place was wired anywhere in the last 20+ years and has an RCD ??

If so any current leakage would trip that...

How old is the house ? Does it have an RCD in the socket circuit ? Is so test it.. (press the button that says test and all your sockets should be dead)..

The fact that you are getting a shock off the sink as will as appliances would lead to to believe that wither you have have a big problem or its static..

Get it looked at...

2011

knipex wrote: »

Surely if this place was wired anywhere in the last 20+ years and has an RCD ??

If so any current leakage would trip that...

No, not any current. Only a current >30mA should cause the RCD to operate.

SpaceTime

knipex wrote: »

Surely if this place was wired anywhere in the last 20+ years and has an RCD ??

If so any current leakage would trip that...

How old is the house ? Does it have an RCD in the socket circuit ? Is so test it.. (press the button that says test and all your sockets should be dead)..

The fact that you are getting a shock off the sink as will as appliances would lead to to believe that wither you have have a big problem or its static..

Get it looked at...

It could be coming from anywhere. Lightning and cooker circuits are not RCD protected and a lot of houses predate the requirement to have them on socket circuits.

If it's an earthing or neutral fault it won't necessarily trip anything yet your metal surfaces could be live.

If you happen to touch the wrong surfaces and get a current through your chest you may get electrocuted.

This is a very serious fault and should be dealt with asap. In the mean time you shouldn't be using the installation as it is clearly in a dangerous state.

It's not something you can just treat as an annoyance.

Your getting multiple shocks from the washing machine which to me would indicate the earth's live.

What you're describing doesn't sound like static


Until it's sorted out don't use the installation and especially don't shower !

knipex

2011 wrote: »

No, not any current. Only a current >30mA should cause the RCD to operate.

True..

mikeoneill893

knipex wrote: »

True..

16mA or above can trip them

the no-trip test is at 15mA

eggy81

2011 wrote: »

No, not any current. Only a current >30mA should cause the RCD to operate.

Anything over 15ma can trip them.
They trip at between .5 and 1 times their rated current don't they?

Steve

eggy81 wrote: »

Anything over 15ma can trip them.
They trip at between .5 and 1 times their rated current don't they?

Cheap ones do. Quality ones do what it says on the box - 30mA

If you have RCDS with 16mA trip level then anything with a switch mode power supply will drive them nuts. Phone chargers, laptops, any modern electronics.

eggy81

Steve wrote: »

Cheap ones do. Quality ones do what it says on the box - 30mA

If you have RCDS with 16mA trip level then anything with a switch mode power supply will drive them nuts. Phone chargers, laptops, any modern electronics.

I thought they were supposed to trip at between .5 and 1 times their current.
This sheds some light on a problematic rcd I've been dealing with.

SpaceTime

They trip between 15 and about 22mA.

mikeoneill893

"A Hager 30mA RCD will not trip at 15mA but will trip at a point above 15mA and below 30mA"

http://www.hagerelectro.com.au/downloads-services-support/faq/84.htm

mikeoneill893

i've never done any ramp testing so i'm not familiar

maybe steve is right and they're calibrated for 30mA

why the fubar should rcd's be tripping anywhere between 16-30 out of the box and not 30mA

it's gonna create a lot more potential for nuisance

Bruthal

mikeoneill893 wrote: »

i've never done any ramp testing so i'm not familiar

maybe steve is right and they're calibrated for 30mA

why the fubar should rcd's be tripping anywhere between 16-30 out of the box and not 30mA

it's gonna create a lot more potential for nuisance

Not if 16 to 30 was always the average. Increased nuisance would only be noticeable if the average trip level did actually reduce compared to before.

mikeoneill893

Bruthal wrote: »

Not if 16 to 30 was always the average. Increased nuisance would only be noticeable if the average trip level did actually reduce compared to before.

so the no trip test is 15mA......


the trip test is at 30mA...........




therefore rcds must trip at a point between 16 and 30mA


(copyright einstein)

Bruthal

mikeoneill893 wrote: »

so the no trip test is 15mA......


the trip test is at 30mA...........




therefore rcds must trip at a point between 16 and 30mA


(copyright einstein)

Yea but unless we know the average of all RCDs in the country, it would be hard to say that finding out they trip at 20 for example, would mean more nuisance tripping than is usually seen.

mikeoneill893

Bruthal wrote: »

Yea but unless we know the average of all RCDs in the country, it would be hard to say that finding out they trip at 20 for example, would mean more nuisance tripping than is usually seen.

ya i wasn't implying that


i just meant less potential nuisance at 29 than 19 for example

Bruthal

mikeoneill893 wrote: »

ya i wasn't implying that


i just meant less potential nuisance at 29 than 19 for example

Yea that's true alright.

Steve

mikeoneill893 wrote: »

so the no trip test is 15mA......
the trip test is at 30mA...........
therefore rcds must trip at a point between 16 and 30mA

No, the trip test is 30mA. That's what the regulations / standards say.
There is no defined 'no-trip' test, it varies my manufacturer.

Also bear in mind that not all milliAmps are the same, it depends on the waveform of the imblance. A human being electrocuted, in theory, will produce a nice sinusoidal imbalance that is easy to work with. Other devices can create lesser RMS imbalances but with higher peaks that exceed the thresholds and this is where nuisance trips arise.

If you really want to know the science of it, have a read of this.

As I said earlier, better quality units are more tolerant because - and I'm guessing here - it's probably easier and cheaper to manufacture a device that trips *somewhere* between 16 and 30 mA than it is to manufacture a device that trips between 28 and 30mA.

Doom

Are the pipes bonded to Earth...? Or maybe not tightened down enough, this may cause a poor earthing in the house.
Your electrician should have done an earth continuity test...it would have shown up any earthing problems.

mikeoneill893

Steve wrote: »

No, the trip test is 30mA. That's what the regulations / standards say.
There is no defined 'no-trip' test, it varies my manufacturer.

yes trip test is 30mA....according to regulations



no-trip test is conducted at 15mA is it not?


it doesn't vary does it?

Steve

mikeoneill893 wrote: »

no-trip test is conducted at 15mA is it not?


it doesn't vary does it?

I don't know, I don't actually do much RCD testing so I'll take your word for it.

This tech note seems to suggest 62% of trip level as an acceptable no-trip test - in this case it would be 18.6mA for a 30mA RCD. Again, I'm not an expert on no-trip testing.

mikeoneill893

neither do i

but no-trip test is always 50% of rated trip current-it doesn't vary


manufacturers tolerances do

as you say the better quality rcds may be closer to 30mA trip on a ramp test

Steve

Anyways... better get back on topic.

The only real way to sort the OP's issue is to do a proper earth loop impedance test on all exposed metalwork back to the incomer.

It could be a broken neutral touching metal somewhere - it would explain the mild shocks as it would create a potential on exposed parts as it used the earthing system as a return to the neutralising link at the meter.

mikeoneill893

prob the first thing you'd do alright

loop impedance testing

can't be much to it

adrian92

My first thought was to agree that it seems like static charge. Mildly but of no danger. I am still inclined to think it is this.

I do not know if anyone else has suggested that you ensure your RCD (device to protect people if they touch a live part) - assuming you do have an RCD at your electrical Distribution Board.


But there could be something else happening.

Is there any time pattern to these occurences , have you noticed?