Appliance plugged into cooker socket shows earth leak

bpowell555 · 21 May 2021

Hi, I get an earth leak (red light on screwdriver touched to appliance chrome casing) from a grinder plugged into a cooker socket. Its fine on another socket so I figure the socket is duff. It trips the RCD every so often too. I replaced the element in the oven a while ago as the cooker handle was a bit buzzy.

Where's the fault most likely and is there anything I can do to check? Could it need a replacement socket or maybe where the cooker is connected?

Cheers!

winston1 · 21 May 2021

bpowell555 said:
Hi, I get an earth leak (red light on screwdriver touched to appliance chrome casing) from a grinder plugged into a cooker socket.

Doesn’t mean anything, could be capacitive induction. Screwdrivers are for undoing/doing up screws not testing earth leakage.

Is this grinder a double insulated appliance?

bpowell555 said:
as the cooker handle was a bit buzzy.

What does that mean?

bpowell555 said:
Where's the fault most likely and is there anything I can do to check? Could it need a replacement socket or maybe where the cooker is connected?

Cheers!

Without proper test equipment who knows? Sockets can fail, people can leave or cut earths off.
For your own safety call in a spark.

Harry Bloomfield · 21 May 2021

bpowell555 said:
Hi, I get an earth leak (red light on screwdriver touched to appliance chrome casing) from a grinder plugged into a cooker socket. Its fine on another socket so I figure the socket is duff. It trips the RCD every so often too.

It reads as if the cooker is not earthed, which is rather serious.

bpowell555 said:
I replaced the element in the oven a while ago as the cooker handle was a bit buzzy.

Again, it is not earthed you should stop using it and turn off the supply until it is properly repaired. It makes no sense to replace an element, because a handle is 'a bit buzzy'.

ericmark · 21 May 2021

Harry Bloomfield said:
It reads as if the cooker is not earthed, which is rather serious.

I would agree, this

socket tester with loop will test there is an earth, and also if the RCD is working, the type without loop will not really help, it seems very likely no earth so £44.50 for tester likely better spent getting an electrician to fix it.

bpowell555 · 21 May 2021

Harry Bloomfield said:
It reads as if the cooker is not earthed, which is rather serious.

Again, it is not earthed you should stop using it and turn off the supply until it is properly repaired. It makes no sense to replace an element, because a handle is 'a bit buzzy'.

Hmm ok I thought it was common knowledge a duff element in an oven can cause earth leakage but you know best.

bpowell555 · 21 May 2021

Cheapo socket tester suggests L N reversed which is usually earth fault. Does it follow the oven is not earthed because the socket has the fault? The grinder I don't think is double insulated.

Harry Bloomfield · 21 May 2021

bpowell555 said:
Hmm ok I thought it was common knowledge a duff element in an oven can cause earth leakage but you know best.

I didn't not say it couldn't, I didn't even get involved in discussing that aspect of your issue - you were suggesting the metalwork of your cooker appeared to be live, that was my primary concern.

bpowell555 said:
I replaced the element in the oven a while ago as the cooker handle was a bit buzzy.

Was what you said and if you were asking - yes a failed or failing element can most certainly trip an RCD. 'Cooker handle buzzy' and screwdriver lighting up, suggest that cooker is probably live and extremely dangerous.

plugwash · 21 May 2021

I presume by a "cooker socket" you mean the socket on a cooker control unit e.g.

It's not impossible that the socket itself is faulty or that some numpty wired it in a way that passes the earth through to the cooker but does not connect it to the cooker control unit.

but it's IMO far more likely that the earth wire has either fallen out or was never connected in the first place. In that case it would indeed affect both the cooker and the socket.

I'd start by looking behind the cooker control unit, then if I didn't find any faults there I would move on to looking in the consumer unit.

bpowell555 · 21 May 2021

Ok can see the cooker and socket share the same earth. I cant see anything wrong on the socket so would suggest either the cable is fooked (big problem), maybe the socket but seems a long shot, or the RCD connection?

bpowell555 · 21 May 2021

plugwash said:
I presume by a "cooker socket" you mean the socket on a cooker control unit e.g.

It's not impossible that the socket itself is faulty or that some numpty wired it in a way that passes the earth through to the cooker but does not connect it to the cooker control unit.

but it's IMO far more likely that the earth wire has either fallen out or was never connected in the first place. In that case it would indeed affect both the cooker and the socket.

I'd start by looking behind the cooker control unit, then if I didn't find any faults there I would move on to looking in the consumer unit.

Sorry took a while to work out how to shrink photos, uploaded now!

Harry Bloomfield · 21 May 2021

bpowell555 said:
Sorry took a while to work out how to shrink photos, uploaded now!

That looks basically OK. When you feel the buzz and get a light on your screwdriver, what else are you touching?

It could be that the oven is actually properly earthed, but what ever else you may be in contact with is live or has some leakage.

Do you have a multi-meter?

bpowell555 · 21 May 2021

plugwash said:
I presume by a "cooker socket" you mean the socket on a cooker control unit e.g.

It's not impossible that the socket itself is faulty or that some numpty wired it in a way that passes the earth through to the cooker but does not connect it to the cooker control unit.

but it's IMO far more likely that the earth wire has either fallen out or was never connected in the first place. In that case it would indeed affect both the cooker and the socket.

I'd start by looking behind the cooker control unit, then if I didn't find any faults there I would move on to looking in the consumer unit.

I'm n

Harry Bloomfield said:
That looks basically OK. When you feel the buzz and get a light on your screwdriver, what else are you touching?

It could be that the oven is actually properly earthed, but what ever else you may be in contact with is live or has some leakage.

Do you have a multi-meter?

The buzz stopped when I changed the element. (it was really mild). The red light on the screwdriver doesn't light if i plug the grinder into a socket the tester says is wired correctly. If I touched my coffee machine (metal) which is on a different socket to the grinder while the grinder was on I could get a shock hence my post. I realised it wasnt a fault with the grinder but the socket....

I do have a multi meter yes

Harry Bloomfield · 21 May 2021

bpowell555 said:
The buzz stopped when I changed the element. (it was really mild).

Changing the element, should not have made any difference at all - if the cooker was properly earthed.

Set your meter to and ac range higher than 250v (maybe 750 or 1,000v). Connect one of the probes to a water tap, assuming it is metal, then the other probe to your cooker's metal work;
the coffer machine's metal;
the grinder plugged into your cooker and then the other socket you mentioned.

Report the reading of the meter, for each.

bpowell555 · 21 May 2021

Harry Bloomfield said:
Changing the element, should not have made any difference at all - if the cooker was properly earthed.

Set your meter to and ac range higher than 250v (maybe 750 or 1,000v). Connect one of the probes to a water tap, assuming it is metal, then the other probe to your cooker's metal work;
the coffer machine's metal;
the grinder plugged into your cooker and then the other socket you mentioned.

Report the reading of the meter, for each.

Cheers. Assume the socket should be on? I've got it disconnected atm

Harry Bloomfield · 21 May 2021

bpowell555 said:
Cheers. Assume the socket should be on? I've got it disconnected atm

Try both ways, because at the moment we are struggling for clues..

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