new ring main installation tripping out

[HawkEye244]

Installation of about 20 new sockets serving 2 rooms, something is tripping the RCD but not the MCB. What could be causing this? It's a second hand MCB I purchased on ebay as I couldn't find volex anywhere else. The peculiar thing is that it does not look like the other MCBs, could it be faulty?

Tested continuity of the live, neutral and earth cables using a multimeter and the readings came back fine. Bit stumped.

 

[ban-all-sheds]

Come now, you run a cable from one socket to the other, it's not rocket science. The fear mongering is tiresome. We all know how easy it is

Get an electrician.

 

[bernardgreen]

Tested continuity of the live, neutral and earth cables using a multimeter and the readings came back fine. Bit stumped.

Measure Live to Earth and Neutral to Earth, should be very high impedance ( > 2,000,000 ohms )

 

[HawkEye244]

Hi bernard, does the circuit need to be live for me to do that? I know how to test continuity on dead cables

 

[bernardgreen]

Hi bernard, does the circuit need to be live for me to do that? I know how to test continuity on dead cables

NO disconnected, you cannot measure resistance ( impedance ) with voltage on the wires.

To be honest by asking that question you convince me you do not have the basic knowledge necessary to test the installation for safety,

Get an electrician involved.

 

[ban-all-sheds]

To be honest by asking that question you convince me you do not have the basic knowledge necessary to test the installation for safety,

A lot of us have been convinced of his lack of basic knowledge of more than just testing for quite some time.

 

[HawkEye244]

NO disconnected, you cannot measure resistance ( impedance ) with voltage on the wires.

To be honest by asking that question you convince me you do not have the basic knowledge necessary to test the installation for safety,

Get an electrician involved.

No need. Everything is available online. Nevermind then.

 

[Risteard]

Installation of about 20 new sockets serving 2 rooms, something is tripping the RCD but not the MCB. What could be causing this? It's a second hand MCB I purchased on ebay as I couldn't find volex anywhere else. The peculiar thing is that it does not look like the other MCBs, could it be faulty?

Tested continuity of the live, neutral and earth cables using a multimeter and the readings came back fine. Bit stumped.

You are a dangerous clown and should be banned from carrying out electrical work and from posting on this forum.

 

[HawkEye244]

lol

 

[Iggifer]

lol

If it’s so easy, as you love to point out. Why do you have a fault on a new circuit?

 

[HawkEye244]

If it’s so easy, as you love to point out. Why do you have a fault on a new circuit?

think it might be when i was cutting through the skirting with the multitool and nicked the neutral and just left it there

any idea why the rcd trips and the mcb doesn't? seems like a neutral to earth problem

 

[winston1]

any idea why the rcd trips and the mcb doesn't? seems like a neutral to earth problem

Well they protect against different things don't they?

 

[securespark]

If you know you have damaged a cable, why didn't you fix it?

There could be an insulation breakdown between the N and E.

 

[mwatsonxx]

when i was cutting through the skirting with the multitool

Never heard of a skilled spark doing something like that. Why did you do that?

 

[HawkEye244]

If you know you have damaged a cable, why didn't you fix it?

There could be an insulation breakdown between the N and E.

The neutral was exposed but I don't think it's enough to cause a earth leakage unless of course it's wedged against something. The copper exposed is no more than 3mm2, it wasn't touching anything so i left it.