RCD trips

[DAVE E C]

Hi, I have just had a new consumer unit fitted, its a split load unit, my problem is that the lighting circuit trips when i switch on two particular lights ( but not every time ).
The lights have round transformers fitted to them and are pretty heavy units, the main light has 16 x 10w halagon bulbs and the other has 12 x 20w bulbs, they are switched seperatly but from the same bank of 3 switches receiving power from the same cable.

Can anyone shed some light on the cause.

 

[Spudnik]

I think you need to get your electrician back to do some tests, which he should have done before changing the CU to make sure this sort of thing doesnt happen.

Oh, and welcome by the way.

 

[brucelee]

good advice from jason

if done by someone else then get them back to rectify the fault which they should have found when testing before board change

 

[Des 56]

If an electrician fitted the consumer unit,then its that person who should be investigating the tripping problem not you as the customer
Or did you fit it yourself, without testing the existing installation

 

[mozzo]

I would agree,the person who did the CU change should be called back in. Before a CU is changed the cables / installation should be tested, that way you know what to expect when the CU is changed. This adds cost to the installation but best practise otherwise you can get unexpected results.

 

[bugsy]

In rush current from transformers, providing the Zs is in tolorance change mcb's from type b to type c

 

[bugsy]

Inrush current from transformer providing the Zs ins in tolorance chage mcb from type b to c

 

[MarkieSparkie]

Dave, The advice given by others here is spot-on, get the electrician back to test the circuit, if all is normal, then inrush current is likely to be the cause and he will be able to change the type of MCB to allow for this situation. The tests are vital before jumping to this conclusion however, because poor workmanship during the erection of the lights could also cause similar effects.

 

[Octopus]

Presumably you were given a EIC (Electrical Installation Certificate) by the Electrician?

Please letus know what happens after they've been back

 

[DAVE E C]

Update.
Sorry its not an RCD but a MCP that fails on the lighting circuit, its been checked out by the electrician that fitted the unit when he returned to fit new lights in a new bathroom.
He says it could be,
A short between the live and nutural or a fault with the transformers which are the big round ones. He changed the 6a trip for a 10a trip but this did not solve the problem so has returned the 6a trip, we will see how it goes over the next few days and call him back if required. The problem is that we had a loft conversion done 20 years ago and the electrics left alot do be desired and are now under the a polished hard wood floor and not easy to get to. I should have left the old fusebox in as it never caused any problems, this is what i get for trying to update your system.

 

[bugsy]

I still say inrush current from toridorial transformers

 

[topquark]

If it's an MCB that's tripping then it's a load related problem, which he should be able to find/identify.

 

[topquark]

I still say inrush current from toridorial transformers

toroidal

 

[simpson93]

I should have left the old fusebox in as it never caused any problems, this is what i get for trying to update your system.

atleast you know this fusebox is working.

 

[bugsy]

toroidal

Thank you - they'll invite you to admin next