Lights flickering, sockets MCB tripping

[rec]

Help!

We have a new-ish house (2 years old) and the last 24 hours we have had the sockets fuse on the RCD trip three times but we are struggling to nail it down to a specific appliance. We also have small spotlights throughout the house which keep flickering like crazy. It appears to get worse the more appliances we have on but there seems to be no set pattern. When it first tripped this morning there were no 'heavy' appliances running (washing machine, etc.) The flickering has been going on for a few weeks and we thought it was a sign that a spot was about to blow, but I think it is related to the tripping problem. Turning appliances on/off doesn't cause it to trip - it seems to go at random. We wonder if we have a dodgy connection somewhere?

Before we call an electrician we thought we ask for some advice. Has anyone come across this sort of problem before? We have a typical set of appliances (dishwasher, tumble drier, washing machine, etc.) plus an alarm system.

Thanks in advance for any help.

 

[Steve]

What exactly is tripping? What is written on the switch that trips.

A CONSUMER UNIT is the big box with lots of MCBs and RCDs in it.

An RCD is a big switch with a test button, usually twice the width of an MCB. It will have a breaking capacity (40A, 63A, 80A, 100A) and a trip rating (30mA, 100mA (or 0.03A, 0.1A)). An RCD generally protects several circuits.

An MCB is a single module item and simply as a switch along with its rating (such as C32, B32, B6, B10, C6) etc. An MCB protects one circuit.

So what is it? And what circuit(s) does it protect?

 

[rec]

It's an MCB in the consumer unit (a Square D). The label says 'Sockets'. When a spotlight goes it always trips the one labelled 'Lights' - we have never had the 'Sockets' one go before.

The 'Sockets' MCB includes B32 on the label. I forgot to mention that we have power in the garage and this MCB also tripped (labelled B16.)

 

[electronicsuk]

Perhaps you have a loose tail somewhere - could be at the meter, CU, or isolator if there is one installed in between. This can cause some odd things to happen, and sounds plausible if your lights have been flickering for weeks in advance.

The lighting MCB tripping when a lamp blows is not at all uncommon and not a fault in itself.

EDIT: OK, just noticed you now mention that a 16A MCB for the garage is tripping. This is not normal behaviour at all, although can only guess right now as to what the fault might be. Sounds as if your best bet will be to call a spark who can see the job in hand.

 

[Guitarguy]

Might not be anything to do with this at all but...

Are any of your neighbours having problems? Service joint on the mains electric cable feeding your house breaking down maybe?

Just a thought

 

[rec]

I'll ask the neighbours tomorrow (although the house next door is empty) and call an electrician. I'll report back.

Been OK since 7 this evening although we don't have as many appliances running.

 

[martinxxxxxx]

If you are able to cure this problem without using the services of an electrician I will take my hat off to you.

If the 16A MCB in the garage is tripping that indicates that there is something in the garage connected to the power that is drawing more than 16 amps, do you have any idea what that may be? If you did then you may just have found the root cause of your problems. As it is very difficult for something that is not in the garage to cause this MCB to trip.

Hope this helps

Martin

Edit Spoolings

 

[ColJack]

it wouldn't be next door anyway, it will be 3rd house up / down from yours.. the other 2 are on different phases to you.. so ask a few of them..

don a pair or two of marigolds and GENTLY wiggle the thick grey cables connecting the CU to the meter, and the meter to the main fuse..
if there is ANY crackling sound call out the DNO immediately and tell them what you heard ( and you may want to embelish a little with "smell of burning" or " hot to the touch cables"..maybe even a little "blue flash"...)

 

[martinxxxxxx]

don a pair or two of marigolds

What is the voltage rating of these?

Surely knipex ones would be better. Bet you have not fitted the MCB I gave you yet?

Martin

 

[ColJack]

went in the same day I got them, working great thanks..

 

[martinxxxxxx]

Wow I am impressed my gaf is the sparks equivalent of a mechanics car. I never get round to doing anything here.

Talking of sparks, about those gloves?

I have come across loose supply connections a couple of times before, both times they were very loose and I thought they must of been loosened on purpose. Is there any other way that could be very loose (ie not from the effects of just heating and cooling)?

Martin

 

[ColJack]

incompetence of the meter guy when they changed from 16mm to 25mm?

heavy handed meter guy ( stripped / cross threaded the screws )?

 

[rec]

All fixed - it was a dodgy connection in the meter box - it actually fizzed and sparked in front of the electrician once we turned everything on (he'd already suspected either the consumer unit or something in the meter box outside.) The SEB were there within 2 hours and the problem has been solved. I kept the old security block thing - one of the thick cables is totally charred and all the plastic inside the meter had melted. Looks like the screws weren't done up tight enough - quite a common issue apparently.

Here's a picture.

Thanks for all the advice BTW.

 

[Guitarguy]

Ahh... the good old meter man didn't double check the screws for tightness!! naughty naughty!

Pretty common like they said

 

[ColJack]

woohooo.. nailed it ..