Power at one breaker, not the other and no tripped breakers.

Not so quick question for anyone willing to help me.

September last year I ran a 6mm 3 core swa from my uncles house up to his summer house as the main supply. I added another small db (like a garage DB) in the house under the board and ran a cable from the live side of the main household breaker to the new db. This then ran through a main RCD earth leakage breaker to a 40Amp single pole breaker up to the summer house. There is nothing up there other than lights and a few sockets for a computer/heater and such like. I used glands and earth tags, putting an m6 but and bolt on the tag with a crimped earth to the main earth bar to earth the steel wired armour itself. Everything worked fine up until this month. I left my him to run the cable in the trees telling him to use cable cleats, of course he used aluminium fixings instead and I hadn't seen this until I went up to find out why it all stopped working. Basically I had 230 volts on the feed out from the breaker in the new house db, and I had nothing at the top of the garden indicating there was a damage in the cable, but no breaker had tripped. Considering how I used the earth tags to earth the steel armour as well as a cable in the 3 core swa, how could this possibly not trip the breaker?

Any help on this would be brilliant sorry for the life story but it means you know all the facts.  

Would also like to add that I went up to sort it out assuming it was a damaged cable talking a joining kit but before I did that I changed all the glands and remade the cable ends etc and everything is working again Any help is appreciated

cheers

I'd be looking at a missed cage on the busbar as a first stop,

steptoe said:

I'd be looking at a missed cage on the busbar as a first stop,

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There was 240 volts across the cable going out to summer house, but nothing across the cable at the summer house (until I remade all connections and both ends) could you explain what you mean please 

When tightening breakers onto a busbar it is very easy to get the "finger" on the busbar on the wrong side of the clamp, the screw tightens up but doesn't grip on the bar. You can get power going through it but at some point it loses contact, possibly due to vibration or some other cause, this is one of the reasons why consumer units have recently began to "spontaneously combust", basically people thinking they've tightened everything when they haven't.

Exactly @phil d

phil d said:

When tightening breakers onto a busbar it is very easy to get the "finger" on the busbar on the wrong side of the clamp, the screw tightens up but doesn't grip on the bar. You can get power going through it but at some point it loses contact, possibly due to vibration or some other cause, this is one of the reasons why consumer units have recently began to "spontaneously combust", basically people thinking they've tightened everything when they haven't.

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Thanks @phil d and @steptoe, will make sure this is secured properly. Don't want my uncles house burning down!

stick in an LFB approved  box and its guaranteed* not to burn down

*  its already been proven that an LFB approved metal CU cant contain a fire...

Andy™ said:

stick in an LFB approved  box and its guaranteed* not to burn down

*  its already been proven that an LFB approved metal CU cant contain a fire...

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Really... tell me more

loose N connection in metal board... place burned down... not really much more to say

Andy™ said:

loose N connection in metal board... place burned down... not really much more to say

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But wasn't that an old metalclad board, not a new LFB approved amendment 3 board?

It was a MEM TP board was it not?

Surely better quality than the tin coated  chocolate you can get from screweys?

Blue Duck said:

It was a MEM TP board was it not?

Surely better quality than the tin coated  chocolate you can get from screweys?

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That was my point.

Lurch said:

That was my point.

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Your on fire tonight lurch!

:slap

Blue Duck said:

Your on fire tonight lurch!

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Oh no, I'm not amendment 3 compliant.......

Lurch said:

But wasn't that an old metalclad board, not a new LFB approved amendment 3 board?

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LFB requirements is simply not readily flammable or something like that, basically made from ferrous material. id say an old metal DB fits that description, so its an LFB approved board. and it didnt contain a fire due to loose connection which is what they wanted to do

would be easier to make the board a bit bigger and stick a fire extinguisher in there

No guys you are wrong wrt Amd3 boards.

The requirement from "LFB" was to remove a source of fuel for any fire, not to contain anything.

The issue was the boards catching fire because they were made of flammable material.

We'll not go into why.

Thus the requirement for being made of non-combustible material, nothing more.

Surely the heat from an electrical fire is enough to make most materials combust.?

Blue Duck said:

Surely the heat from an electrical fire is enough to make most materials combust.?

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See now you're bringing common sense into it which is unfair as it is a bit late now.

Sidewinder said:

No guys you are wrong wrt Amd3 boards.

The requirement from "LFB" was to remove a source of fuel for any fire, not to contain anything.

The issue was the boards catching fire because they were made of flammable material.

We'll not go into why.

Thus the requirement for being made of non-combustible material, nothing more.

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Oh, are we meant to be fitting metal MCBs now then,?

Surely the 'old' CUs were made from the same material as MCBs, ? :C

I asked the NICEIC why boards could not be made of the same materials as the MCBs......they said they would   get back to me

they haven't 

this was over 12 months ago