16A breakers on lighting circuits

[SLIPSHOD & SLAPDASH]

Although 1.5mm cable could take this load, what about light fittings, pendants, fans etc ?

I think this should be coded 2 on a PIR ?

 

[sellers]

technically the cable in the light fitting, fan, etc should be designed to take the load of that fitting. Like 1 unfused spur being allowed on a ring.

 

[Apache]

Although 1.5mm cable could take this load, what about light fittings, pendants, fans etc ?I think this should be coded 2 on a PIR ?

What's the issue? We have a socket rated 13A on a 32A ring?

:|

 

[kme]

If it IS a lighting circuit, then, unless the connected accesories are capable of withstanding (20AX switches etc.), then I`d code 2 it mate.

HOWEVER, if it was designed to work like that, (which is where sight of the EIC would help), then it would be a case of verifying that the luminaires & switches have not been altered, or the circuit extended with 1.0.

Zs could be an issue, too.

KME

edit: `pache: most domestic light switches are rated 5A, though 10 and 20 are not unheard of. The 13A limit is provided by the fuse in the plug - it isn`t possible to draw 32A from a double socket, OR expect the switch to make/break that sort of current. Yes?

 

[bengie]

but the labelled rating of sockets/SFCU/DP isolators is only 13A or 20A as he has said so they are underated for a 32A MCB.

 

[SLIPSHOD & SLAPDASH]

13A accessories are rated for the current that can be drawn through them, and as they are protected by a 13A fuse that's ok. My question was regarding a lighting circuit where no other protective devices are fitted except the 16A breaker at the source. If a fan or light fitting was to short circuit or , say a choke short out ?

Also as mentioned the majority of switches are marked 6 or 10A max, but with no further protection.

Of course there are no design or installation certs for these jobs.

 

[septiclecky]

If it IS a lighting circuit, then, unless the connected accesories are capable of withstanding (20AX switches etc.), then I`d code 2 it mate.HOWEVER, if it was designed to work like that, (which is where sight of the EIC would help), then it would be a case of verifying that the luminaires & switches have not been altered, or the circuit extended with 1.0.

Zs could be an issue, too.

KME

edit: `pache: most domestic light switches are rated 5A, though 10 and 20 are not unheard of. The 13A limit is provided by the fuse in the plug - it isn`t possible to draw 32A from a double socket, OR expect the switch to make/break that sort of current. Yes?

Thing is though a light fitting will only draw the current it needs to operate

No but it is possible to draw 26A if you have 2 13A loads on a double socket:innocent

 

[ProDave]

Have you measured the full load current with all lights on?

I doubt it will be anywhere near 16A, if it is, the lighting circuit really needs to be split in two.

My guess is a 16A breaker was fitted to prevent nuisance tripping when a lot of light are turned on together (a whole office full of flourescent fittings?)

If so a better solution would be a 10A C curve breaker.

 

[sparkytim]

What load do the light switches carry in NORMAL use?

Unlikely any 1 switch has +10 Amp load.

Fault condition completely different issue

Light switch not expected to survive short circuit fault only conductors.

BRB Pg74 433.3.1

 

[mike_s]

I asked my college tutor a similar thing and, he turned around and said the mcb is there to protect the cable, so as long as the cable can withstand the rating on the mcb then it is ok. is that correct?

 

[bengie]

thats how i have always understood it mike but got shot down for this before.

 

[septiclecky]

I asked my college tutor a similar thing and, he turned around and said the mcb is there to protect the cable, so as long as the cable can withstand the rating on the mcb then it is ok. is that correct?

It's the same as a plug top fuse it is there to protect the cable and not the appliance.

 

[Risteard]

The Regs state that up to 16A is acceptable.

 

[SLIPSHOD & SLAPDASH]

The Regs state that up to 16A is acceptable.

Please tell me what reg number

 

[kme]

It's the same as a plug top fuse it is there to protect the cable and not the appliance.

Can I ask where that piece of info comes froim mate? I wasn`t aware of that.

 

[SLIPSHOD & SLAPDASH]

I have just got back from an emergency call out. Lighting circuit in a house had blown and would not reset. I found a burnt out choke in a fluorecent light in the kitchen that had really been cooking itself and finally tripped the 6A breaker. What could have happened if that was on a 16A breaker ?

 

[bengie]

very little i expect, it probably tripped due to it shorting out internally.

 

[Risteard]

Please tell me what reg number

559.6.1.6

 

[bengie]

its almost like they wrote that reg simply for this post.

 

[Apache]

559.6.1.6

its almost like they wrote that reg simply for this post.

what does it say?