Increasing lighting circuit MCB ampage

[sunningdalelad]

I have just replaced a ceiling light with an Endon fitting, this fitting has
12 x 20 watt halogen bulbs and a built in transformer. The light works most of the time but occassionally the 5 amp MCB trips out (even when this is the only operating light on the circuit) . Is it safe to uprate this to either 6 or 10 amp.

 

[Chivers7]

What size cable feeds you lighting?

 

[sunningdalelad]

Sorry to be vague but I am not at home at the moment, the cable seems to be standard domestic lighting cable, twin & earth in grey sheath approx 1 cm wide.

 

[Taylortwocities]

The problem is the high inrush current that some fittings can cause. It can be solved by upgrading some things but we need to check some stuff first.

5 amp mcb, sounds like is this one of the plug in ones that replace a rewireable fuse? Can we see a pic? Or tell us what is written on it. It will probably say B5 or B6 either on the front or on the side.

You should not upgrade fuses unless you test that the new fuse will trip in the required time and that the cable can handle the increased current.
you need specialised test equipment to do this.

 

[sunningdalelad]

The MCB make is Hager, from recollection it does not just slot in, it is attached by screws. The Circuit Board was installed in Jan 1994 when house was rewired. Does this tell you enough or should I wait until I get home?

 

[Taylortwocities]

Need to know whats written on it. Later then...

 

[sunningdalelad]

Managed to speak to tecnical dept at Endon, apparently it needs a type c MCB due to initial surge. Thanks for help.

 

[JohnD]

read what Taylortwocities said.

 

[Taylortwocities]

Thanks, took the words right out of my keyboard

 

[securespark]

"You took the words right out of my keyboard...It must have been while I was hitting it..."

A new take on a Meatloaf song...

You cannot just change the mcb for a different type rating until you have checked the EFLI at the destination of that circuit.

 

[sunningdalelad]

Acted before reading further posts, still alive! Have replaced Hager B6 MCB with Hager C6 MCB as Endon advise that the transformer causes high in rush current and requires either Cat C or Cat D. With Cat C in place there is less tripping but still some. Will therefore try Cat D.

 

[Taylortwocities]

NO NO NO. Why post on this forum and then ignore the advice????

each time you change the mcb from B to C to D the earth fault loop characteristic is halved. If you change it to a D there is a better than evens chance that the fuse wont trip quickly enough in the event of a fault = fire etc etc.

ENDON should not give you that advice. They cannot know.
Only someone with the correct test equipment can determine if its OK to do so on your installation.

 

[sunningdalelad]

Thought you might say that, won't go any further until an electrician has tested system. Thanks for your advice. Do you know where I can buy hair straighteners!?( Just kidding)

 

[JohnD]

I wonder if it is a lighting package intended for domestic use, and it has the correct lamps in it and the correct length leads? If so, it's hardly suitable if it keeps tripping domestic breakers.

Maybe a soft start package would have been more suitable.

Or maybe there's something going on with the circuit we don't know about.

I wonder if it's kitchen downlighters or under-cupboard lamps.

I wonder what sort of switch it has.

 

[sunningdalelad]

I wonder if it is a lighting package intended for domestic use, and it has the correct lamps in it and the correct length leads? If so, it's hardly suitable if it keeps tripping domestic breakers.

Maybe a soft start package would have been more suitable.

Or maybe there's something going on with the circuit we don't know about.

I wonder if it's kitchen downlighters or under-cupboard lamps.

I wonder what sort of switch it has.

The fitting is an Endon 704 - 12SC with 12 x 20 watt halogens and a transformer built into the ceiling rose. It is certainly a domestic fitting.