Shocks from cooker

BeardySi

It seems there's something wrong with our electrics. Metal parts on the hob, oven and anything plugged into the socket on the cooker isolator switch are all live and giving shocks.

I've isolated the whole circuit at the fuse box and it'll stay that way until the landlord gets an electrician in. Was just wondering if anyone could suggest a likely cause?

meercat

most likely its an earthing problem.no earth somewhere on the circuit.definately need a registered electrical contractor to check it out.leave the circuit off until its sorted(as you have done)

Steve

Get the electrician to replace the cooker switch with one that doesn't have a socket. Theses are generally not RCD protected and are potentially lethal - and also have been illegal to fit for many years.

Most likely there is more than one issue here, a broken earth and a live contacting metal. Leave it switched off till the electrician checks it out.

Risteard81

meercat wrote: »

definately need a registered electrical contractor to check it out.

He's (she's) in Belfast so an REC doesn't come into it. But (s)he does need a competent Electrician.

Risteard81

Steve wrote: »

Get the electrician to replace the cooker switch with one that doesn't have a socket. Theses are generally not RCD protected and are potentially lethal - and also have been illegal to fit for many years.

He/she is in Belfast. BS 7671:2008 (2015) which is the relevant Standard on this occasion does permit their use. So they are certainly NOT illegal in Belfast. It may or may not be RCD protected, although it has been the case for some time that all socket outlets not exceeding 20A must be RCD protected.

Tuco88

Risteard81 wrote: »

He/she is in Belfast. BS 7671:2008 (2015) which is the relevant Standard on this occasion does permit their use. So they are certainly NOT illegal in Belfast. It may or may not be RCD protected, although it has been the case for some time that all socket outlets not exceeding 20A must be RCD protected.

Thought it was socket circuits > 32amps did not require rcd protection myself.

Risteard81

Tuco88 wrote: »

Thought it was socket circuits > 32amps did not require rcd protection myself.

Nothing to do with the circuit protection. It is socket outlets with a rating exceeding 20A (which excludes 13A socket outlets to BS 1363).

Steve

Apologies Risteard81, you are probably correct on the legal side of it.

My advice to the OP remains, if it saves a life then regardless of the legal position, it was worth it.

Risteard81

Obviously I meant includes rather than excludes 13A socket outlets!

2011

Although the OP may be describing an issue outside ROI installing RCD protection on socket circuits make sense.

The laws of physics work the same everywhere.

Risteard81

But it has been stated already that RCD protection is required for the socket outlets.

It is also very clear from the OP that the installation is in the Six Counties. (Check the location.)

Bruthal

2011 wrote: »

.

The laws of physics work the same everywhere.

They do, but how life functions within the constraints of physics laws can differ from place to place.

If we bring in RCDs on cookers for example, which is probable eventually (rcbo probably), does that mean we were operating potentially lethal appliances before that? It could be said everything we do is potentially lethal. But if they did become the norm on cookers, in time people will be saying that you must have an RCD on them, its lethal without it. Yet it's fine now.

RCDs are cheap reliable and simple devices. They make a very small risk smaller in my opinion, rather than make something potentially lethal safe. So they are an obvious practical safety device.

RCBOs will possibly become the norm. RCDs doing multiple circuits is a bit messy in comparison.

Stoner

Very much the case, the single pole rcbos with neutral reference connections used in the UK will just replace MCBs imo

2011

Risteard81 wrote: »

It is also very clear from the OP that the installation is in the Six Counties. (Check the location.)

Until the OP states otherwise I don't think that we can conclude that this installation is definitely in the north.

BeardySi

That it is! Thanks folks, getting far too technical for me now! Sparky due today so I guess we'll wait and see...

2011

Treadhead wrote: »

That it is! Thanks folks, getting far too technical for me now! Sparky due today so I guess we'll wait and see...

North of the border? Fair enough.

2011

Bruthal wrote: »

They do, but how life functions within the constraints of physics laws can differ from place to place.

If we bring in RCDs on cookers for example, which is probable eventually (rcbo probably), does that mean we were operating potentially lethal appliances before that? It could be said everything we do is potentially lethal. But if they did become the norm on cookers, in time people will be saying that you must have an RCD on them, its lethal without it. Yet it's fine now.

RCDs are cheap reliable and simple devices. They make a very small risk smaller in my opinion, rather than make something potentially lethal safe. So they are an obvious practical safety device.

RCBOs will possibly become the norm. RCDs doing multiple circuits is a bit messy in comparison.

+1

I am not a fan of installing RCD protection on cookers when they are connected as a fixed appliance.

Bruthal

2011 wrote: »

I am not a fan of installing RCD protection on cookers when they are connected as a fixed appliance.

Why not, nuisance tripping?

2011

Bruthal wrote: »

Why not, nuisance tripping?

I think it is OTT, just like bathroom lights on an RCD.

Bruthal

2011 wrote: »

I think it is OTT, just like bathroom lights on an RCD.

Bathroom lights present a risk by having an rcd, leaving an occupant in the dark if there is nuisance tripping.

A cooker with bad earthing could be dodgy enough. Its a hands on appliance, beside a bonded sink in many cases, unlike the lights. Still low risk of course. But so are sockets with no RCD really. But with RCDs being relatively cheap, and easy to install, they are a good idea, at least on sockets.

2011

Bruthal wrote: »

A cooker with bad earthing could be dodgy enough.

Yes, but "theoretically" the earth on this fixed appliance has been checked by the electrician.

Still low risk of course.

That is my point. I mean if we are going to keep making things "safer" where do we stop?

But so are sockets with no RCD really.

I agree with this as any device in any condition could be plugged in.

But with RCDs being relatively cheap, and easy to install, they are a good idea, at least on sockets.

What does an RCBO cost now? €30ish ?

Bruthal

2011 wrote: »

Yes, but "theoretically" the earth on this fixed appliance has been checked by the electrician.

Lots of things are better in theory than reality. I know what you`re getting at though.

I agree with this as any device in any condition could be plugged in.

You don`t agree you mean. Its still low risk. If it was high risk, we would regularly hear of people getting shocks. It takes quite a nasty shock to trip an rcd, having done it myself 2 or 3 times. It would be extremely rare for anyone to trip one receiving a shock, ive never heard of it (apart from myself). Sockets were around a long time before RCDs.

That is my point. I mean if we are going to keep making things "safer" where do we stop?

Stop driving cars, dont fly, dont go out of the house. Install 50 volt installations. After all, some will say if it saves 1 life, its worth it. Then they will drive to the shop without a thought that hundreds die each year driving. But it is easier to reduce the already low risk of socket electrocution using an rcd, than it is to give up the much higher risk of driving.

What does an RCBO cost now? €30ish ?

Not sure. Still relatively cheap anyway. If we had to buy one once a month, that might be expensive. But, people will rather buy the cheaper mcb alright.

Steve

In my humble experience..

Cookers (ones with rings, not more modern induction or halogen) don't have RCD protection because it's impossible. The elements are porous and leak. They absorb moisture and humidity when not switched on and glowing red.
This means they have an inherent constantly variable leakage current and therefore cannot be protected by residual current measurement.

I know this from building and testing industrial ovens that use the same element material as domestic cookers (and electric HVAC for that matter) and they will even trip the 300mA RCDs if they are left idle for a week or two.

Risteard81

Steve wrote: »

Cookers (ones with rings, not more modern induction or halogen) don't have RCD protection because it's impossible.

Since 2008 it has been common for cooker circuits in the north in a domestic dwelling to have RCD protection due to the use of cables buried in walls at a depth of less than 50mm with no suitable mechanical protection (e.g. pyro; SWA; earthed steel conduit).

In practice there is seldom any problem with RCD tripping.

Steve

Risteard81 wrote: »

Since 2008 it has been common for cooker circuits in the north in a domestic dwelling to have RCD protection due to the use of cables buried in walls at a depth of less than 50mm with no suitable mechanical protection (e.g. pyro; SWA; earthed steel conduit).

In practice there is seldom any problem with RCD tripping.

Didn't know that.

What spec are they? 30mA?

Bruthal

Steve wrote: »

Didn't know that.

What spec are they? 30mA?

It was in through the end of the coil type elements, where the white insulator is, that moisture probably used to enter. As you say, rings left off for any length of time would become more affected.

Risteard81

Steve wrote: »

Didn't know that.

What spec are they? 30mA?

Yes, 30mA as they are for additional protection.