2 issues - elecs tripping & installing kitchen appliance

[Clem Bones]

Hello,
We bought a house last year and have had much of the electrics renewed including circuit board / fuse board and a stack of new sockets & light switches installed, old boiler and shower taken out and new ones installed.

1) Recently after about an hour painting the living room, the radio went off and I found that (all) the electrics had tripped out. I flipped the "master" fuse back on and everything was fine for about 10 minutes and then it tripped again. Tried again, a few mins later, same again.
The same thing happened a week later when I was next in decorating, althought the radio was plugged into a different socket. It stayed on initially for about an hour or so and then tripped and would then only stay on for a few minutes.

The boiler, lights, kettle etc have been left powered on for extended periods and the elecs have never tripped out like this before, so it seems that either the radio or the sockets / circuit (downstairs front) is the cause. I've plugged the radio in to various sockets upstairs and didn't experience this issue.

- Before I call out the sparky, could this fault be caused by the radio rather than the electrics? It sounds to my (non-electrician) mind that the radio is taking a while to "overload", but once it does, it trips out quickly and repeatedly thereafter. I can try and get in to test a different radio or other device plugged in in the living room at some point if necessary.

-------

2) We are having a new kitchen installed next. Due to arrive are:

Electrolux double oven (built in)
Electrical connection rating (W): 2800
Current (A): 11.6666666666667
Voltage (V): 240

Electrolux gas hob (built in)
Voltage (V): 230

Plus an extractor and a standard (integrated) dishwasher.

Obviously, each of these are going to require power supply.
I'm told that modern ovens can just be plugged straight into a standard wall socket because the current is less than 13A.

- Although this may be the case, is there a benefit in connecting it to a "proper" cooker point instead?

- Will there need to be 4 sockets (one for each device), or is it standard practice to connect any combination of these devices together?

- Is it worth getting the sparky to install the power supply to try and reduce the kitchen fitters' bill? The sparky is relatively cheap and we can get him to do other things while he's in. But as the kitchen's fitted, the fitters would probably know the best position for the sockets (i.e hidden behind the new units) and in fact would likely make the whole of my second issue moot. Apart from they may inflate the cost.


Any answers / advice is appreciated.

==Clem Bones==

 

[JohnD]

Too many questions here.

- Is it worth getting the sparky to install the power supply to try and reduce the kitchen fitters' bill? The sparky is relatively cheap and we can get him to do other things while he's in. But as the kitchen's fitted, the fitters would probably know the best position for the sockets (i.e hidden behind the new units) and in fact would likely make the whole of my second issue moot. Apart from they may inflate the cost.

It is generally considered that a professional electrician is better at doing electrical work than a kitchen fitter is.

Is yours sufficiently qualified to issue an installation certificate, which is required (among other things) for the kitchen work, or are you going to pay the Building Inspector instead?

 

[JohnD]

too many questions here

...(all) the electrics had tripped out. I flipped the "master" fuse back on and everything was fine for about 10 minutes and then it tripped again.

The thing that tripped, is it an RCD or an MCB? What numbers and letters are printed on it?

If you can lay your hands on a digital camera and put up a photo that will be a great help.

How qualified was the person who did the electrical work?

 

[Steve]

A radio will not overload a 100A MCB. It will blow the fuse in the plug first. Something is tripping your RCD main switch.

Fault finding:
Find what appliances were running when the RCD trips next. Especially watery appliances (boiler, washing machine, kettle etc). Ovens are good at tripping RCDs too.

When an RCD trips it is detecing earth leakage. This is common in watery appliances and ye olde motors, and can be very intermittent (fault current very close to, but not actually at, the trip current, ocassionally popping over the trip current).

An electrician will be able to diagnose the problem quicker than we can, or than you can. Unless you can isolate entire circuits at a time. Not usually feasible in a used building!

EDIT: by the way, YOU will probably be able to fit the kitchen electrics better than the kitched fitters, never mind calling a spark! But you cant due to part p, unless you notify.

 

[Clem Bones]

I've been down the house tonight.
I tried flipping the "Sockets" fuse back on, but it just switched itself back off - that's better than the whole house going off I suppose.

Here's a pic.

As for watery appliances, there's nowt much plugged in - no washer, dryer, dishwasher, oven, shower. The only things plugged in in the entire house are radio, kettle, new boiler. I'm pretty sure the kettle's on the other socket circuit but will check later tonight.

The fuse tripping out is the one that says "Sockets" and is switched off (not the "Sockets Up"). Initially, the "main" fuse on the left hand side (RCCB) tripped, but this now stays on.

Cheers,

CB

 

[Steve]

ok, something was causing an earth leak, and is now shorting L-N when you try to reset the MCB.

Scrap what i said earlier!!! Unplug everything on the circuit. and turn off any switches on the circuit. Try turning it on now. If it still wont reset, you need an electrician, as its a fault on the wiring. Electrician will have the nessecary test equipment.

You never know it could be a faulty MCB! (i hear chint are very bargain-basement)

 

[JohnD]

Looks like a 63Amp RCB being used as whole-house main switch, is rather low (I have a 100Amp one for a biggish house) especially if you have an electric shower and/or cooker

 

[plugwash]

looks like a split load to me, notice especially the "circuits protected by rcd marking"

i've seen split loads with the main switch at one end and the RCD the other before though they are admittedly rare.

 

[securespark]

You need to auto test the RCD to find out if its tripping characteristics are within the prescribed parameters.

You could also ramp test the RCD to find out what current it is tripping out at - anything less than 1/2 the rated current is a fail.

Bear in mind that any RCD test should be carried out on the RCD alone in isolation from any circuitry attached to it.

This means switching off any mcb's connected to the rcd, then disconnecting the neutral from the RCD neutral busbar and making it safe. Then you can test from the outgoing terminals of the RCD, without worrying about the rest of the circuit affecting the readings. But you need specialist kit....

As for the MCB, it could be suffering from thermal effects. Is a neighbouring MCB overheating and tripping out its neighbour? You may well have a circuit fault, so will need to do IR tests on the wiring to check that.

A lot to think about...

 

[Adam_151]

i've seen split loads with the main switch at one end and the RCD the other before though they are admittedly rare.

The older Hager boards were like this (there is one installed in this house) and I think chint boards are also like this (though I only had a quick glance at it)

 

[cozycats]

NO you CANNOT plug in a double oven! ---without the fuse blowing anyway.