Discuss 3p breaker feeding 3 x 1p circuits in the DIY Electrical Advice area at ElectriciansForums.net

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Hi everyone.

I may be blind but I can't find a definitive answer.

Can I use a 3 pole breaker (originally feeding a massive 3 phase heater) to feed 3 single phase circuits?

I've run seperate neutrals for the 3 new circuits and the breaker is rated for the load required - 30a per phase (I'd be installing 3 x 32a breakers if I could, but the age of the board makes this a pain).

Killing all the circuits in the event of a problem won't be an issue - they're all in my workshop.

So - is it permitted?

There are no socket outlets involved
 
It will still function as would a single-pole device but you will lose three circuits if a fault occurs on one. Not the end of the world but probably falls foul of Reg 314.2, what make is the board.
 
Not worried about losing 3 circuits in the event of a fault. Board is a square D circa 1990 full of old black QO breakers.

The whole installation is going to be inspected so it needs to be right - or at least acceptable.
 
Problem with the device you have reused is that it is a Type 4. How have you proved disconnection times will be met.
 
A fault on one circuit shouldn’t effect another circuit?
Also because they are all on the same ocpd would it be classed as one circuit not 3?
 
Oh cool - saw those they're not exactly the same but the look like they'd fit.

I've attached an image - I'm replacing the top 3p breaker.
3p breaker feeding 3 x 1p circuits IMG_20190706_182822 - EletriciansForums.net
 
Thruppence for a breaker. That’s cheap
 
ÂŁ14. that's cheap.had to get a 32A 3p QO MCB for a garage rolling road. ÂŁ116 + VAT.
 
ÂŁ14. that's cheap.had to get a 32A 3p QO MCB for a garage rolling road. ÂŁ116 + VAT.
I don't think Schneider continued the production of the triple-pole devices for very long.
 
if i remember, the rolling road was fed from a 20A 3 phase MCB with a 6.0mm SWA. clowns came and installed a new machine 27A/phase and wondered why it was tripping out on load.
 
if i remember, the rolling road was fed from a 20A 3 phase MCB with a 6.0mm SWA. clowns came and installed a new machine 27A/phase and wondered why it was tripping out on load.

And the same clowns were still sat there in the van trying to drive home
 
"Quick! Put your foot down, tel is coming and he's wrapped in a floral blanket"
 
He turned his back on them
 

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