Fuse Types

[Big_Spark]

Journeyman, the problem with stating things how you did implies that it is perfectly OK to use a 16A MCB or similar device to protect a lighting circuit, when it is not.

I have been involved in huge aircraft hangers at Heathrow and at Military Installations, there the lighting circuits are wired in 2.5mm to get around volt drop issues and the problems of inrush currents caused by the control gear of the lights, but even here we would only ever use a 10A MCB to protect each circuit, with the lighting being controlled by a contactor (but that's another matter)

 

[journeyman]

Then I have been corrected.

I guess that the regulations are wrong and need to be amended.

 

[Big_Spark]

Journeyman, I agree, this is another area where the Regs confuse not inform. Table 55B on page 125 clearly states that 16A breakers are are maximum that can be used for B22, E27 and E40 lampholders, and this is clearly ridiculous.

Unfortunatetly it is a another case of the Engineers who write the Regs not actually talking to those that do the work and understand the practicalities of the job a bit better than a pen pusher.

 

[journeyman]

16A breaker on lighting!! What's your name Bodgit!!

Your talking rubbish journeyman, if someone has told you that then they were bulling you and it is crazy.

BS7671 told me this. I guess the wiring regulations are just bull****.

Not only that, the definition of the word "maximum" seems to be a bit iffy as well.

 

[Big_Spark]

I refer you to my previous post...

 

[journeyman]

I guess the Electrical regulations are written by plumbers.

 

[Big_Spark]

I guess the Electrical regulations are written by plumbers.

Sometimes I think many sparks think the same thing, either that or written by an indecisive politician!

 

[evdama]

Going back to the breakers,is it allowed to have B's and Cs' on the same busbar?

 

[plugwash]

don't think there is any reg against it or anything unsafe about it

C type breakers can be usefull to stop nusense tripping in lighting cuircuits when bulbs blow

 

[securespark]

Plug

Only Type B's should be used for dom light circ's.

If you have nuisance tripping caused by lamps popping off, try a branded lamp with fuses incorporated (like Osram).

 

[Idorenyin]

Hi, please I need some help. I need a full description of a 'D' type J&P fuse paticularly for 11kv.

 

[Idorenyin]

Hi, please I need some help. I need a full description of a 'D' type J&P fuse paticularly for 11kv.

 

[EFLImpudence]

Google ?

 

[ericmark]

I will agree not easy to work out sizes just reading the regulations as one reads 559.6.1.6 it seems to say 16A limit but one also has to consider manufacturer's instructions which also have to be complied with and they rate the BA22d bulb holder at 2A and the ceiling rose at 6A.

The bulb holder is not really a problem as bulbs should have fuses built in so if there is ionisation when they blow it will take out the fuse in the bulb rather than the whole circuit unless you buy them from cheap shops like Ikea who seem to miss them out. It's the ceiling rose which is daisy chained which is the real limiting factor. So if you fit a ceiling rose then that is a JB rated at 5 or 6 amp so that's the limit of the lighting MCB.

Using a type C may stop it tripping before the built in fuse which should be fitted in the bulb but since the BA22d holder is only rated at 2A if the fuse is missing in the bulb when it blows it can weld the bulb contacts to the holder so I would fit a B type in case cheap bulbs are used.

However if you look at the date of the post this should be by now all done and dusted.

 

[Spark123]

Check out the date of the original post!!