Main supply side earth leakage tripping

[Brigadier]

Hello all

Ripped from slumber last night by burglar alarm blaring away.

Found that the (forgive me if this is the wrong terminology) earth leakage thing has tripped. I reset this 3 hours ago, but it has just tripped again, cutting power to apparently everything in the house.

Quite an old house, with this black bakelite-looking Crabtree thing on what appears to be the supply side, fed by two thick red and black cables. It has a yellow push button on it, and "500v" and "60A" marked on it, in white text.

Grey cabling then exits this box, to a pretty new split load distribution board. Nothing has tripped on the new board, just this Crabtree trip.

Apart from replacing a couple of GU10s in the kitchen yesterday afternoon, no electrical work, or new appliances, for a long time.

Checked with the neighbour - they have had no power outages, so I expect it is limited to my house.

Could the Crabtree be failing? Or what else could it be?
As it is apparently supply side, is this a supplier-to-fix issue? FOC?

I like my sleep, and I don't fancy the freezer full of food having to be binned, if it keeps happening!

Thanks in anticipation

 

[Brigadier]

Rushed post a bit in case power goes again.......

 

[JohnD]

post a pic or list all the letters and numbers on the breaker, or better, both.

You might have an old voltage operated breaker that needs replacing.

For the moment, unplug and examine all your electrical appliances with water in them, includer the boiler, immersion heater, outside lamps, shed and pond.

order a new standby battery for your alarm.

It is not the electricity company's responsibility and is almost certain to be on your side of the meter.

 

[AndyPRK]

does it say 500mA ?
50V ?

 

[ericmark]

The earth leakage circuit breaker (ELCB) is split into two types voltage and current the voltage type ELCB-v is now banned we now use only ELCB-c which are better know as RCD's. For domestic these are again split into two groups the 100ma is used where the supplier does not provide an earth and an earth rod is used. The 30ma version is used to protect personal but in the main is not used as a single device normally at least two are used.

Alarms must last at least 12 hours without power and once the alarm triggers it must auto silence within 20 minutes so it would also seem the alarm is faulty.

So first question is what does it say on the ELCB? Once answered we will take it to next stage.

 

[Spark123]

Easiest way to tell is a voltage operated ELCB should have two earth wires connected to it in separate terminals, one to the installation and the other to the means of earthing, usually an electrode in the ground.

 

[Brigadier]

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[maltaron]

That is an old voltage operated earth leakage trip. It appears that you have a modern RCD in your CU so I would get a sparkie in disconnect and scrap it.

 

[Spark123]

It looks like a split load consumer unit to me, so any fault on the left hand side (with the red legends) will not cause the RCD in the consumer unit to trip and still has the potential to trip the VOELCB.
You need a sparky to disconnect and do away with the VOELCB, find the fault that was causing it to trip which will be on a circuit with a red legend below the MCB.
You will probably also end up having a new consumer unit as your supply appears to be a TT hence all circuits should be RCD protected.
Difficult to tell from the pics, but is the consumer unit made by GE and has Wylex MCBs fitted?

 

[OwainDIYer]

I used to have a newer version of that, which dated from 1968, so that one is probably even older.

 

[Lectrician]

The CU is a split load type, so half is not RCD protected.

For the older 16th edition, that ELCB should have been replaced with a 100mA Type S RCD feeding that board. These days with the 17th, you would ditch it, but only if you have a dual split load CU (you don't).

A compromise would be to swap it for a 100mA type S RCD - Not ideal, and not 17th compliant, but would be the best way to go I reckon.

 

[Brigadier]

Spark123 - you are correct; a GE CU, with Wylex MCBs on it. These are variously marked as NSB06, NSB16, NSB32, and an NSB40.

I have had the kettle and coffee makers unplugged for 7 hrs now, and no trip yet - will have to brew up for the lad around 2100, so might see then......

Thanks for help so far

 

[JohnD]

87 years to go...

 

[Brigadier]

OK,

Firstly, thanks all for the help

Now, how to move forward. Please feel free to correct anything below.

1. The VOELCB is very old, and ought to go.
2. The electricity supply is "TT", and therefore all circuits must be RCD-protected.
3. The current CU will not on its own offer all circuits RCD protection.
4. A (non- 17th ed. compliant) workaround would be to have a spark replace the VOELCB with a 100mA type S RCD.
5. Would 4. be "illegal"?
6. The "belt and braces" solution would be for a spark to remove the VOELCB, the current CU, and replace with a dual load CU.

Thanks again

 

[JohnD]

(6a) or keep the CU and fit RCBOs to the non-RCD circuits.

RCBOs are great.

It is rather suspicious that whoever fitted the new CU left the old Voltage breaker installed. Either he lacked skill and knowledge, or he was reckless in short cuts, or both.

You might also need a new earth spike but I recommend you start by asking your electricity supplier if they can give you an earth connection. They often can at reasonable cost.