Advice on an old style fuseboard thats tripped

[mrtapir]

Hi all, my house has one of the old style fuseboards for the mains electrics. This morning I went to have a shower and found that the pump wasnt working, then found other electrics that weren't working.

I took off the cover of the fuseboard and it looks like there is a black stain where the fuse has burned out. This also appears on the inside of the cover. This fuse seems to be labelled 'sparks'. Is this common electricity parlance for something? It seems to be the plug sockets downstairs, plus the shower pump, which must be wired into where the boiler is (downstairs, same as the heating controls which have gone off, but are upstairs).

We had the kitchen redone a couple of years ago and I thought the electrician put the kitchen on a new mcb (which you can see in the picture labelled 'circuit 3 ring main'). However some sockets in the kitchen have tripped, but not the one which is one of those compound sockets with a plug and the oven on/off switch.
I believe this happened during the night, and the only thing that was actually in use was the dishwasher, but I thought that was on the new mcb'd ring main...

I dont really know about any of this stuff so any advice would be very much appreciated. Is it possible/safe to replace the fuse now as an initial fix? I think it would be good to have it all on trip switches rather than old fuses as it seems there might be a small chance of a fire if they go!

Cheers, Rich





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[Taylortwocities]

The device above the fuseboard (CHINT) is an RCD and this also seems to have tripped. But this seems to be associated with circuit 3.
The black stuff seems to be from circuit 2. It MAY be that the black marks are old.

First thing to do is to TURN OFF THE MAIN SWITCH. and take out the fuses and examine them to see if any of them has actually blown.
IF so, put in new fuse wire, push that RCD lever up so it is on and then, carefully, turn on the main switch. If there is still a short there may be a bang as the fuse blows, so watch out for that....

On no account are you to pull fuses in and out with the main switch still turned on. If a short circuit is there then you could suffer burns, or worse.

Let us know what the result is.

EDIT: Also, disconnect & unplug the dishwasher. I would suspect that thel fault is a problem with the D/W and its tripped that RCD.
You cooker will be on a different fuse, that is why it is still working.

 

[mrtapir]

Thanks for replying, I'll check that all when I get home from work.

Is it possible that the electrician that wired the things in the kitchen rewired all the sockets in the downstairs to that new RCD? My initial thoughts was that this RCD was only wired to the oven socket, but from what you have said it makes me think he might have switched the downstairs sockets onto the RCD (this would make sense if the dishwasher caused the trip).... But then I'm not sure where the oven switch would be wired to.

 

[mrtapir]

I've just seen the edit to your post, which was along the lines of my thinking reading your initial response.

 

[ban-all-sheds]

We had the kitchen redone a couple of years ago and I thought the electrician put the kitchen on a new mcb (which you can see in the picture labelled 'circuit 3 ring main').

That's an RCD, not an MCB, and it has tripped.

According to the labelling, it's not on the circuit where the smoke has escaped. But labels can be wrong. Also, is that soot new? Have you ever had the cover off before?

However some sockets in the kitchen have tripped, but not the one which is one of those compound sockets with a plug and the oven on/off switch.

That's because the cooker circuit is separate.

I believe this happened during the night, and the only thing that was actually in use was the dishwasher, but I thought that was on the new mcb'd ring main...

Appliances which use water are prime candidates for causing RCD trips if they develop a leak. Any signs of one?

Will the RCD turn back on? If it does, do any sockets come back to life?

Is it possible/safe to replace the fuse now as an initial fix?

The fuse blew for a reason - unless you find that and fix it, it will go again.

In theory a plug or FCU fuse should blow before the 30A one in the fuse box, so it might not be a faulty appliance.

See about the RCD, and, with the power off, remove the fuse holder from circuit #2, and see if there are any signs of damage beyond a bit of soot. Maybe post photos?

 

[ban-all-sheds]

But then I'm not sure where the oven switch would be wired to.

To one of the three 30A circuits you have. The sockets in the house will be to the other(s).

 

[mrtapir]

OK thanks. My thinking for when I get home is this:

- turn mains off and look at the fuse to see if it has tripped (i dont think i have taken the back off yet so im not sure that the soot is new or already there).

- Check for a leak near dishwasher.

- Unplug dishwasher, turn RCD back on and see if this turns things back on

If this works, should I plug the dishwasher back in again (only if i dont find a leak)?

If there are only three of the fuses with labels, how can i tell what, if anything, is wired to the unlabelled fuses? Do the colours mean anything?

 

[Taylortwocities]

On review. I suggest you isolate the dishwasher and try to reset that RCD first. You may find that that is all you need to do and no fuses have actually blown.

At some time, you should take the time to remove each fuse in turn and determine what each one does. Make a list and post it next to the fuse board.
Remember to turn off power before removing fuses.

My guess, your fuses will be something like (from right to left.

1. Cooker 30A
2. Ring (sockets) upostairs 30A
3. Ring sockets downstairs 30A
4. Immersion/water heater 15A
5. Lights downstairs 5A
6. Lights upstairs 5A.

The coloured dots tell you the size of fuse wire that you MUST use. It is also written on the fuse carrier itself.

Last thought. If you have a fridge/freezer on the faulty circuit, you might want to run an extension lead so the lobster doesnt defrost...

 

[mrtapir]

On review. I suggest you isolate the dishwasher and try to reset that RCD first. You may find that that is all you need to do and no fuses have actually blown.

At some time, you should take the time to remove each fuse in turn and determine what each one does. Make a list and post it next to the fuse board.

yes I plugged the fridge into the socket on the cooker so its ok.

So when I'm checking the fuses, do I just turn the power off, unplug a fuse, turn power back on and see which things dont come on? Then turn power off, plug fuse back in, etc. and carry on until all are done.

 

[ban-all-sheds]

Unplug dishwasher, turn RCD back on and see if this turns things back on

Do that first - it's possible that no fuses have gone.

If this works, should I plug the dishwasher back in again (only if i dont find a leak)?

It might still be the culprit if you don't find a leak - a small spray, now dried up, could do it.

If there are only three of the fuses with labels, how can i tell what, if anything, is wired to the unlabelled fuses? Do the colours mean anything?

White = 5A, and as it says, lighting circuits.

Blue = 15A. Do you have an immersion heater?

Red = 30A. Looks like you have a cooker circuit and 1 or 2 socket circuits, one of which is RCD protected, and which may or may not be the one where there is soot, which may itself not be new.

The only way to find out what's on each circuit is to test to see what works/does not work with different fuses in/out.

 

[mrtapir]

Unplug dishwasher, turn RCD back on and see if this turns things back on

Do that first - it's possible that no fuses have gone.

If this works, should I plug the dishwasher back in again (only if i dont find a leak)?

It might still be the culprit if you don't find a leak - a small spray, now dried up, could do it.

Having got home and done a test it defintely looks like the dishwasher. I untripped the RCD and everything came back on, the dishwasher carried its cycle on and then tripped out again. So I've unplugged the dishwasher and untripped the RCD again and everything has stayed on.

I couldnt find any water or a leak around the dishwasher. Is this the only reason why it might trip the switch?

 

[Spark123]

It could be anything in the dishwasher or associated wiring, at least you now know that you have to wash pots by hand till you get an appliance engineer to have a look (or a new dishwasher)!!

 

[bernardgreen]

If there is a blown fuse then ensure all applainces are turned off and replace the wire with 5 amp fuse wire and then turn on the main switch. Using 5 amp means the "explosion" in the fuse will be less if there is a fault that will blow the fuse again. If the five amp does not blow then it is unlikley the fault is in the wiring and likely to be an appliance. In which case put the main switch OFF and change the fuse wire to the required rating and put the fuse back in. Main switch ON and one by one turn each appliance ON and then OFF If the fuse blows then you have found the fualty appliance.

Also the RCD lever may need to be pushed fully down before it can be reset by being pushed upwards. The RCD appears to be only an RCD so it should be supplied from one of the fuses in the consumer unit.

 

[Spark123]

Sounds like the dishwasher is tripping the RCD to me

 

[ban-all-sheds]

I couldnt find any water or a leak around the dishwasher. Is this the only reason why it might trip the switch?

No - could be a failed heating element.