Main socket switch on fuse board tripping out.

Dinarius

We are just finishing a kitchen extension.

After the wiring went in, the main switch on the fuse board started to trip out intermittently when appliances were plugged into one or other (never the same) of the new sockets.

For example, the vacuum cleaner did it a couple of times, as did the capenter's saw when the floor was being laid.

While the extension was being built, we were doing the ironing in the dining room without any problem. Then, the other day, we plugged the iron in in the utility room (which was unavailable during the building) and the main socket MRCB went again. We tried it in all the utility room sockets. Same problem. None of these sockets are part of the new build.

Just now, we tried it in the dining room again and then in a neighbour's house. The MRCB went in both places.

1. Could the tripping out in the utility room the other day have damaged the iron making it now unworkable? In general, is tripping out bad for appliances that are running at the time - e.g. this has happened twice while my computers have been running.

2. A couple of times when switching back on the MRCB, the swithc on the same row marked 'Kitchen' has tripped out.

I'm assuming that something in the new wiring is the fundamental fault here. The electrician is coming back tomorrow and talking about replacing the MRCB. But, if he was to put in one that is less sensitive (I'm not saying that this is what he's going to do) wouldn't that just mask the fault without repairing it?

Would be very grateful for some advice on this.

Thanks.

D.

2011

Could the tripping out in the utility room the other day have damaged the iron making it now unworkable? /QUOTE]
No

In general, is tripping out bad for appliances that are running at the time

For most things it is not an issue but computers would be an exception.

I'm assuming that something in the new wiring is the fundamental fault here.

That would be my assumption too. Everything worked before, you got some work done and now you have issues with more than one appliance. I would guess that the new socket circuits are sharing the RCD that the old sockets are on.

I would guess that the problem you are experiencing is due to a low resistance reading between earth and neutral on your extension. Sometimes problems like this occur when plaster has not dried out 100%. This can take a few days.

But, if he was to put in one that is less sensitive (I'm not saying that this is what he's going to do)

I am sure you mean RCD. The type used should be designed to operate at 30mA according to the regulations. This will be written on the RCD. I am sure your electrician will sort this problem out quicky, it is a common "teething problem" that is normally easy (and painless) to fix.


If the iron is causing the RCD in more than one house to operate there may be an unrelated issue with it. Irons can sometmes haev evry short lives (or perhaps that is just in my house!)

this has happened twice while my computers have been running

Frequently people put computer circuits on their own RCDs or RCBOs ( an MCB and RCD combined in one unit) so that the cahnces of them tripping are reduced.

Dinarius

Thanks for the comprehensive reply.

The plaster has been dry for weeks. But, the problem has been there since the sockets were installed. I thought that the iron was giving us a repeatable fault (instead of an intermittent one) but it now looks faulty too, as I said.

So, I guess we'll just have to hope that he finds something wrong and fixes it.

Will suggest that the computers are put on their own switch. Thanks for that.

D.

2011

The plaster has been dry for weeks

OK so it is not the plaster.

I thought that the iron was giving us a repeatable fault (instead of an intermittent one) but it now looks faulty too, as I said.

I think you are correct here.

So, I guess we'll just have to hope that he finds something wrong and fixes it.

I am sure he will.
This is an easy problem to solve with the correct equipment, it is just a process of elimination.

Will suggest that the computers are put on their own switch. Thanks for that.

This may not be possible at this stage, it depens on the way it is wired. However it should be simple enough to split the sockets up so that they are not all on the same RCD. That way if an RCD trips you only loose the sockets that are fed from it, rather than all of the sockets in the house.

Dinarius

2011 wrote: »

I am sure he will.
This is an easy problem to solve with the correct equipment, it is just a process of elimination.

What equipment should have to test the sockets?

Thanks.

D.

2011

What equipment should have to test the sockets?

There is a small unit to start off the test process that is quite popular, it looks like this:




Then to complete the testing an earth fault loop impedance tester and a insulation resistance tester(often referred to as a "meggar") is required.

Many electricians nowadays use a combined test unit like this:

Dinarius

Great.

Thanks.

D.

2011

No problem

Let us know how you get on!

davelerave

As already said .It maybe a neutral-earth fault in the new wiring-if class 2 appliances are tripping an existing rcd.
Always safer for the sparkie to fit additional earth-fault protection to avoid 'crossover' with the old wiring

2011

I should have mentioned that an RCD tester is also required. The Fluke tester shown above has this built in.