OSG 10A or 6A MCB lighting

[James Salisbury]

Hi,

I don't have a copy of the On Site Guide to hand, is a 10 A mcb permittied in circuits with pendant light holders?

[BigWallop]

Depends on how many and what is plugged in to them. A 6 Amps MCB is preferable, but if the lighting circuit is going to take anything over 1 KWatts of lighting, then you should install the 10 Amps MCB.

[Lurch]

On Wed, 5 Jan 2005 21:13:40 -0000, "James Salisbury" strung together this:

Yes. It's not the type of fitting that determines the CPD size, it's the rating of cables, contacts and equipment etc...

[Owain]

"James Salisbury" wrote | I don't have a copy of the On Site Guide to hand, is a 10 A mcb | permittied in circuits with pendant light holders?

A circuit with SES or SBC lampholders is limited to 6A. For this reason, if it's a domestic dwelling, it would be good practice to limit lighting circuits to 6A, because an unqualified/incompetent person could change a decorative fitting for one with an SBC/SES lampholder at a later date.

I /think/ BC lampholders can be connected to

[Andrew Gabriel]

Yes, providing there are no SES or SBC lampholders (that's in the main regs, not the OSG). Other factors like cable length, earth fault loop impedance and the type of protective device (i.e. Type B or Type C in the case of an MCB) come into the equation too (and I don't have the OSG on me to look it up), but it generally isn't a problem unless the cable length is very long.

[Andy Wade]

Well it is in a sense because you can't go over 16A for ordinary bayonet (B22), Edison screw (E27) or Goliath Edison screw (E40), no matter what the rating of the cables, etc.

And if any small bayonet (B15) or SES (E14) lampholders are on the circuit the limit is 6A, as has already been pointed out.

[Reg 553-03-01 and Table 55B]

[Lurch]

On Thu, 06 Jan 2005 00:39:46 +0000, Andy Wade strung together this:

I realised my reply was a bit non-specific and had a feeling you'd be along! I suppose I could have qualified the statement with a "in this instance". (Although I did assume standard BC lampholders so that still may not have been the case but YSWIM).