Air Conditioning power supply

[pootle76]

Is it acceptable to run an air conditioning unit from a 13A Fused Spur, or should it be run from a new radial circuit?

The unit is a heat pump inverter type with a max power draw of 2.62kw at 230v in heating mode (nominal 1.86kw) and an inrush current of 8.2A.

Thanks

 

[Steve]

Its acceptable, but it'd be better to run a new circuit if possible.

 

[ban-all-sheds]

Tut tut.

Mustn't call them air conditioning units.

They are air source heat pumps nowadays.

 

[pootle76]

Further to my first question:

The Air source heat pump (air con ) ) will be going into a new conservatory. There will also be 1.6kw of under-floor heating.

An electrician will be coming to carry out the wiring but I would like to get an idea of how this can be best carried out before he arrives.

The conservatory is in easy reach of the Downstairs and Upstairs ring main. It would be a bigger (and more expensive) job to run new circuits from the CU as it is on the other side of the house to the Conservatory, but if that’s what it takes then so be it.

My feeling is it would be unwise / dangerous to put both a potential 2.6kw of AirCon and 1.6kw of under-floor heating onto a ring main, throw in a 3kw kettle and 2000w vacuum on a cold day and you could have 40amps! What would the electricians among you recommend?

Thanks...

 

[r.bartlett]

An inverter will not have an inrush current so you need to check your unit spec again.

 

[davelx]

An inverter will not have an inrush current so you need to check your unit spec again.

Not all reversibles are inverters - mine isn't, it just has a reversing valve and the compressor is a straight capacitor start switched by a relay.

 

[pootle76]

The value for inrush current is taken directly from the specification sheet in the Mitsubishi Technical manual and is the same value as the nominal heating input.

Any thoughts on the wiring circuits for the conservatory?

 

[Taylortwocities]

Wiring Regulations recommend that a separate circuit is provided for fixed loads in excess of 2KW.
This is suggested as a way of reducing the current load on ring final circuits.

I would put in a new radial for this.

 

[1john]

I would run two new radials, should a circuit fail you would still have a heating device in there in the winter months and neither will affect your socket circuits.

 

[r.bartlett]

An inverter will not have an inrush current so you need to check your unit spec again.

Not all reversibles are inverters - mine isn't, it just has a reversing valve and the compressor is a straight capacitor start switched by a relay.

Thanks for that -although being in the trade since 1982 I really didn't need it- but what has this got to do with what I said?

If you want to make a general comment -feel free but don't drag me into it...

 

[davelx]

An inverter will not have an inrush current so you need to check your unit spec again.

Not all reversibles are inverters - mine isn't, it just has a reversing valve and the compressor is a straight capacitor start switched by a relay.

Thanks for that -although being in the trade since 1982 I really didn't need it- but what has this got to do with what I said?

If you want to make a general comment -feel free but don't drag me into it...

Ah - my mistake, somehow I missed the word "inverter" in the original post

 

[ericmark]

Wiring Regulations recommend that a separate circuit is provided for fixed loads in excess of 2KW.
This is suggested as a way of reducing the current load on ring final circuits.

I would put in a new radial for this.

This is the real point and what it is or what the inrush is does not really have much of a bearing. Appendix 15 page 362 gives very little room for manoeuvre and Taylorwocities has give the best answer.

 

[ColinJacobson]

Tut tut.

Mustn't call them air conditioning units.

They are air source heat pumps nowadays.

An Air Sourced Heat Pump can be an air conditioning unit. In many cases it is not, providing only heat. A ASHP must not be termed as an a/c unit. It can provide cooling, but in most cases will not and is not an a/c.

It pumps heat from the outside air and into a cylinder, or directly into a heating system, etc. Many can be reversed and pump heat from a duct battery to the outside, or better into a cylinder.

One thing is clear you DO NOT call a general a/c an ASHP.

 

[ColinJacobson]

Wiring Regulations recommend that a separate circuit is provided for fixed loads in excess of 2KW.
This is suggested as a way of reducing the current load on ring final circuits.

I would put in a new radial for this.

I agree that a new radial should be installed as this appliance would be on for long sustained periods. But what constitutes a "fixed load"?

In most cases a washing machine and dishwasher are on the same kitchen ring drawing more than 2kW each. These are regularly used appliances and at some point will be on at the same time, and then the electric kettle is on for tea as well on the same ring.

So does the more used dishwasher need its own radial?

 

[Taylortwocities]

I agree that a new radial should be installed as this appliance would be on for long sustained periods. But what constitutes a "fixed load"?

Appendix 15 suggests loads such as cookers ovens and hobs. I would imagine as these can be a substantial load on a ring final over long periods.

Appendix 15 gives suggestions as to how the loads on ring finals can be reduced, and that is by taking larger loads off the ring.

At no point does is say "must" but given the nature of this load a good designer would put in a separate circuit.