Please put my mind at rest

[Hottub]

hi guys I have had an electrician come and put some wiring in ready for a hot tub delivery.

I passed on a electrical document sent to me by the hot tub company which had 6mm on it.

He has run a armoured 2.5mm 3 core cable from the main board and a dedicated 32amp mcb to an external rotary switch ( about 3 metres away ) also 32amp. From the switch he has run the same 2.5m 3 core around to where the hot tub will be ready to be connected ( no more than 4m away ).

He says its more than enough but as I've seen 6mm on the wiring diagram I'm worried.

So shall I stop worrying? Or demand he use 6mm? Or find a different sparky?

Thank you for your time.

 

[Hottub]

Sorry forgot to add the hot tub is 32amp and has a 3kw heater.

 

[telectrix]

he's out of order. a 2.5mm should not be protected by a 32A MCB. at the best, it's capable of 27A, so the next nearest below that is a 20A MCB. if a 20A MCB can cope, it's fine, but on a 32A MCB a 4mm or 6mm cable is appropriate

 

[telectrix]

also, btw, regs. state that manufacturers instructions are taken int account, so if they say 6mm, anything less would transfer any blame for problems to the spark who had ignored them. get him back and insist on 6mm.

 

[westward10]

What he said that cable is underrated.

 

[LankyWill]

What's the bets he had some 2.5 armoured left on the van from another job and thought "that will do". Get the chancer back and insist/demand on 6mm at his expense and time.

 

[telectrix]

it may well be that 2.5mm cable is adequate for the load, but the rating of the MCB should be below the design current, unless he's working on the principal that the tub is a fixed load and thus can dispense with overload protection. tin hat ready.

 

[ED17]

also, btw, regs. state that manufacturers instructions are taken int account, so if they say 6mm, anything less would transfer any blame for problems to the spark who had ignored them. get him back and insist on 6mm.

^^^^
This

 

[Hottub]

Brilliant thank you so much I will get him back and make him fit 6mm. Is the 32amp mcb fine?

 

[westward10]

Who decided on the 32A it seems excessive for a 32A load.

 

[Hottub]

Him

 

[westward10]

Seems very odd that he knows the rating of the hot tub then either totally miscalculates or is not competent.

 

[buzzlightyear]

which hot tub company connecting in, and is it RCD protected.

 

[telectrix]

all boils down to this:

1. what is the load current of the hot tub? get that from rating plate.
2. from the above, what size cable is required? from BS7671.
3. from the size of the cable, what rating should the OCPD be? Ib<In<Iz.

simpleesss.

 

[Dave OCD]

Not forgetting length of run and ambient temp/insulation etc 'en route' Tel.