A/C installation "outdoor to indoor" cable query

[Zdb]

So I went to a job yesterday where the A/C engineers had upgraded an air conditoning system and fitted new units. I was there just to switch on the power and do the testing and certification on the electrical side of things.

They used the existing supply cable from the old unit (6mm) and MCB (B32).

The bit that confused me was that the cable going from the outdoor unit to the indoor unit was only 1/1.5mm.

Surely this is too small for the 32a MCB or am I missing something?

Please can someone advise as I don't usually get involved in A/C installations.

Thanks.

 

[Toneyz]

We have got this set up on a job we are on at the moment where a 6.0mm SWA goes to outdoor unit and they have run 1.0mm flex to indoor unit I assume that it is internally fused.

 

[telectrix]

the load of the internal unit is a fixed load within the ccc of the 1.5mm or whatever cable is used. therefore overload protection for this cable is not needed.just s/c protection, which is provided by the 32A.

 

[Pete999]

All the cable fro condenser to evaporator does is run the fan in the evaorator and is internally protected.

 

[telectrix]

even if it isn't, it's OK.

 

[Pete999]

even if it isn't, it's OK.

Morning Tel

 

[telectrix]

ditto, pete.

 

[Wilko]

Hi - don't suppose you noted the AC model ?
Just thinking it might be worth looking at manufacturers doco.

 

[Spoon]

Depending on cable type, if the cable is 1mm isn't that too small, according to table 52.3 of the regs?

 

[Wilko]

Yes, but perhaps relying on manufacturers spec as its flex (last section of that Table)

 

[Spoon]

Yes, but perhaps relying on manufacturers spec as its flex (last section of that Table)

True mate. The OP didn't specify what cable it was. That's why I put 'Depending on cable type'

 

[telectrix]

True mate. The OP didn't specify what cable it was. That's why I put 'Depending on cable type'

do you mean round or flat?

 

[Spoon]

Not sure what the regs mean by 'flexible cable' as all cables are flexible...when you bend them enough....

 

[Wilko]

At risk of being a goody two shoes here, but I'm concerned that 1mm may not survive a low Zs sc on C32 (?) without damage if it was already running hot. Perhaps apply adiabatic?

 

[Zdb]

It was SY multi flex