Faulty Consumer unit?

[bluesxman]

I've just had the electricty cut out in our house. The lights flickered a bit then the power went. At first I thought it was a power cut as no MCBs had tripped. But turning the master switch on the CU on and off made the power come back for a brief second.

So some questions for anyone kind enough to answer:

1. I've restored power by moving the switch down a few millimetres closer to the off position - is this safe???
2. What is likely to be the problem? Could it just be a faulty mcb or something more sinister?
3. How could a switch which is static 99% of it's life develop a fault like this?

Thanks in advance for any help.

 

[JohnD]

(edited - I've moved the important bit to the top)

Moving the dolly of the switch to make it work probably means it will burn out again soon. Regardless of the cause, start asking around your friends and neighbours for reliable local electricians, and phoning them (you cannot do it yourself, among other reasons because the incoming cables to the switch will be live and the switch might break up when disturbed). Most of them will probably be tucked up for the weekend now but you will need it replaced quite urgently. Keep electrical loads to a minimum until then. The electrician will want to know the brand and age too.

For further comment and possible explanation:

tell us the age and brand of the CU (also its colour, this is not a joke).

The main switch ought to be marked with a power rating, e.g. 100Amp, 80Amp, 63Amp (this might be on a label or embossed into the CU cover near the switch - what is that?

Give us an idea of the load - electric heating? Big electric cooker? Electric shower(s)? Welding gear? Home smelter? Extensions and outbuildings added on since the original installation?

If you have a digital camera and can put up a pic of the CU and its surrounding cables and meters, we'd love that.

BTW I'm assuming it's just a main switch, not an RCD? Does it have a "Test" button on it?

 

[Spark123]

My opinion is you need it sorted as soon as possible, it is not OK to just leave it. Is it a modular type switch? Are you able to isolate the feed into the consumer unit? Is the fuse box an old rewirable fuse type?

 

[bluesxman]

Thanks for the quick replies. I guess my main concern is whether this is a callout job or something I can arrange after the weekend.

To answer what I can of your questions.

The CU was in the house when we bought it 8years ago, the house is 20 years old.

Brand is Hager Powertech, colour beige, no "Test" button.
The main switch has the following on it:
100A
380/415V ~ 50HZ

I wouldn't have said the load is anything other than average; electric cooker, washing machine tv etc. Heating is all gas. No extensions/outbuildings.

The only other information I have is on a sticker on the unit:

[code:1]
Consumer Unit BS 5486 PART 13 AMD 4519
Conditional Short Circuit Current 16 KA
CAT REF: C05 8.01
[/code:1]

Thanks again for the help and advice.

 

[JohnD]

Then it "shouldn't" have failed. I don't know how good Hager are, I believe they are an inexpensive brand. 100A means it is operating within its rating. I have known main switches go loose and crackly when they're 40 years old, but not at 20 if it is not being frequently switched on and off. Switches are usually tested to have a life of thousands of operations.

Best hurry up and get it replaced.

 

[Lectrician]

Sounds like a dodgy main switch or a loose connection on the cable or busbar side. Possibly the busbar is on the wrong side of the jaw-type terminal.

A loose connection may be tightened, or the busbar correctly installed......but the switch may have already suffered damaged due to heat.

It needs repairing ASAP.

 

[bluesxman]

Fault was traced to the mains switch on the CU. It has now been replaced and everything given the once over.

Thanks again for the replies.

 

[ban-all-sheds]

Is there an RCD part way along?

 

[bluesxman]

I don't think so, but then again I wouldn't know exactly what to look for!