Would length of circuit make RCBO trip

[Norv]

Doing some electrical connections on the motorway for some CCTV & one of the connections to the camera is approx 500 metres from the supply.

When I put the switch up on the RCBO it wouldnt reset. Disconnected all the load on the cable & it still wouldnt reset. Ive walked the length of the cable & not found any damage but it is a long way to inspect it fully, so I just wondered if the length of cable have something to do with the RCBO not resetting ?

Dont know why I think that, but thought I'd ask ?

Cheers

 

[plugwash]

Have you done an insulation resistance test?! if not why not? if so what were the results?

 

[Norv]

Yes I did & the results were all >299. Only did it on 500V, maybe I should have done it on 1KV

 

[Spark123]

Nah - if the results are 299M> @ 500v then the IR is fine.
You have connected the neutral to the RCBO neutral terminal and not the CU on haven't you?

 

[ColJack]

R1+R2 reading?

 

[electronicsuk]

Presumably the RCBO will reset with the cable disconnected from the outgoing terminals, more or less ruling out the RCBO itself?

 

[ColJack]

how much capacitance would you get on a run that long?

 

[Spark123]

Depends on type of cable

 

[Lectrician]

And why an RCBO?

 

[bernardgreen]

I have known 30 mA RCDs to trip on the capacitive coupling in 400 yards of twin and earth mains cable.

 

[Goldberg]

Dont know why I think that, but thought I'd ask

Does this mean that our motorways are being wired by people whose knowledge is so inadequate that they can't solve problems (of their own creation) without asking questions on an Internet forum?

 

[Norv]

it was a discussion goldberg. I was asking about rcbos not how to do my job. Anyway engineers for this particular maintenance company decide what cable and circuit breakers to use and i do the connections and testing.

 

[Goldberg]

it was a discussion goldberg.

It's still discussion, and it's not unreasaonable to ask why, if the task you're discussing is part of your "job", you don't know how to solve a problem that occurs in the course of your "job" without asking a question on an Internet forum.

Whatever trade I work and have I've worked in, if someone else has designed something that I'm implementing and/or testing, and I find a problem, then I go back to the designer.

If you've used the components that the engineer specified, and determined that the components aren't faulty, then [why] have you not asked the design engineer why it's tripping?

 

[Chri5]

Why don't you wind your neck in.

Have you any idea how contrary you come across in some of your posts, male PMT is it ?

 

[holmslaw]

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