3p breaker feeding 3 x 1p circuits

[Philip Saunders]

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

 

[westward10]

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.

 

[Philip Saunders]

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.

 

[westward10]

Good old Schneider still produce replacements.

QO132VSC10 - QOvs - miniature circuit-breaker - 1P - C curve - 32A - 10kA | Schn

QO132VSC10 - QOvs - miniature circuit-breaker - 1P - C curve - 32A - 10kA

www.schneider-electric.co.uk

 

[westward10]

Problem with the device you have reused is that it is a Type 4. How have you proved disconnection times will be met.

 

[Charlie_]

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?

 

[Philip Saunders]

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.

 

[westward10]

Schneider bought and Square D and to their credit still produce devices. Bit of vat and delivery, bargain.

Square D QOE (QO132VSC10) 32 Amp 10kA Single Pole Type C 240V Miniature Circuit Breaker MCB > QOvs (formely QO) MCB's > Circuit Breakers > Square D > Electrical Supplies > Zetmet Ltd

Square D QOE (QO132VSC10) 32 Amp 10kA Single Pole Type C 240V Miniature Circuit Breaker MCB available from Zetmet Ltd discount electrical supplies

www.electricaldiscountedsupplies.com

 

[littlespark]

Thruppence for a breaker. That’s cheap

 

[telectrix]

£14. that's cheap.had to get a 32A 3p QO MCB for a garage rolling road. £116 + VAT.

 

[Philip Saunders]

£14. that's cheap.had to get a 32A 3p QO MCB for a garage rolling road. £116 + VAT.

I have a few spares......

 

[westward10]

£14. that's cheap.had to get a 32A 3p QO MCB for a garage rolling road. £116 + VAT.

I don't think Schneider continued the production of the triple-pole devices for very long.

 

[Baddegg]

£14. that's cheap.had to get a 32A 3p QO MCB for a garage rolling road. £116 + VAT.

Ouch!

 

[telectrix]

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.

 

[Charlie_]

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