Light fittings and type D mcbs

[jjnr78]

Hi all. I'm facing a little problem. We have fitted some light fittings that prefer type D mcbs (manufacturer said type c probably ok, but they are tripping). Unfortunately Hager do not make a type D breaker for my 17th ed CU. any ideas how to overcome the issue?
thanks

 

[MDJ]

Hi all. I'm facing a little problem. We have fitted some light fittings that prefer type D mcbs (manufacturer said type c probably ok, but they are tripping). Unfortunately Hager do not make a type D breaker for my 17th ed CU. any ideas how to overcome the issue?
thanks

Can you let us know what type of light fitting it is? a D type mcb is the wrong type IMHO for lighting, much more suitible for heavy industrial items LOL

 

[Lucien Nunes]

Also, circuit rating, number of fittings per circuit and the switching configuration (e.g. are they all switched together). Is there anything else on the circuit?

 

[Darkwood]

What is your lighting design, it seems from initial assumptions their is a lack of design criteria to this circuit with regard to inductive accumulative inrush of multiple fittings that are energised together....

Does the MCB trip when lighting is switched on or after its been on a while?

Will fitting a type D invariably give you none compliance to trip times under S/C conditions?

As you suggest you are on a 17th edition board with no type D's for it i must conclude you have a domestic board .... can you supply all the info' touched upon from your replies.

 

[iamelectric]

are they LED by any chance

 

[tony mc]

I take it that the circuit has been tested and it could be that the MCB is just doing its job !

 

[jjnr78]

Sorry guys, not enough info:
it's the mains voltage LED wall washers causing the problem. Also the circuit needs 30mA RCD protection. It's designed for a 10A. I'll have to check exact loadings as it was one of team with the issue not me.

- - - Updated - - -

All tested too...and checked again. Everything is clear

 

[Darkwood]

Have you accounted for inductive loading?
The lamp wattage isn't key to the inrush nature of the driver so it isn't proportional to how much load the circuit pulls, its the number of units that are energised simultaneously that is what you need to account for - if you have simply loaded up the lamp wattage and converted to amps you will not have designed the circuit correctly...

The mcb will have Tech' references as to how many lamps maybe switched on of a given lamp type this is usually available for free online this is the first step to designing your lighting circuit... I really wish colleges would teach students this and not leave it to advanced courses ... it ill prepares so many new Sparkies out their to which you may find at your cost....

 

[i=p/u]

1.8 are you referring too dark wood

 

[Darkwood]

I don't like to do all the work for them... regardless of the 1.8 factor mcb have a limited tolerance to accumulative inrush which within the domestic realm isn't usually an issue well until you get one with lots of down lights LED or ELV and one switch.

 

[iamelectric]

how many fittings on the circuit?

 

[Deleted member 9648]

Hager used to make cartridge fuse holders for their DB's...fitted a standard MCB way. Might get over your problem.

 

[Engineer54]

Type D MCB's on lighting circuits?? I hope you're Zs values up upto scratch to use them kiddies, or are you going to rely on RCD's as is now commonly seen??

As others have pointed out, get the design right and you'll have no problems using type B's or C's...

 

[MDJ]

Another very frustrating thread, I feel like I need to kick next doors cat, why oh why do an OP let a thread die without further explanation? They come on and ask a question, we ask a few back so we can help and they disappear. There is no abuse or nasty comments here and yet boom they have vanished.

 

[jamie-spark]

Hager still do d curve mcbs
Although they don't make the part for the consumer unit range (6ka)
They make them for the industrial range (10ka) which fits the consumer units
But as others have said there is a lot to consider before whacking it in
http://www.toolsandelectrical.com/i...tchgear/hager-ndn-mcb-type-d-single-pole.html