Aircon Unit and Ringmain

[DJUK]

I'm converting a garage and have two free slots on the CU, which I need for the ringmain and lighting circuit which will go in there.

I also want to put in a fixed Aircon unit, 3Kw, and I want to know if I can put this on the new ringmain or if there are any regs which say it must be on it's own circuit.

I won't be wiring this in myself, but I want to avoid a whole new CU if possible.

 

[Spark123]

It is recommended that any fixed appliance which takes 2kw> is on it's own circuit.

 

[RF Lighting]

There is no specific regulation, but is is recommended that any fixed load greater than 2kW should not be fed off a ring circuit.

 

[ColJack]

feed the lighting circuit off a fused spur from the ringmain and then you have a spare slot for your air con...

don't forget that an air con will need a C or D type breaker because of the starting currents..

 

[ericmark]

The bit of the regulations which refers to fixed appliances on ring mains has been corrected so you can read it yourself Here

 

[ColJack]

I see no information in the corrigendum about the connection of loads to a ringmain..

the diagram has been altered to replare "as a rule of thumb" with "historically" with regards to floor area served by a ring or radial, and a no longer used BS number for FCU's has been removed.

where is this correction you mention?

 

[Steve]

don't forget that an air con will need a C or D type breaker because of the starting currents..

I have NEVER seen an air conditioner on a D breaker. Most I have seen on C's, mine at home is on the ring main, on a B32 - its 2kw.

The fact is most quality air conditioners will cope on a B breaker.

 

[DJUK]

I don't suppose it makes any difference that it's Energy Rated A for efficiency? I already have a portable aircon unit which is upstairs which just plugs into a 13A socket, this new one comes with a 13 amp plug and so I expect it would do the same, I just wanted to make a better job of it than that...

So, all things considered, it's not the recommended method, but I could technically put it on the ringmain and it would still pass for Part P etc?

 

[ColJack]

sorry, I'm used to industrial things that sit on Tesco roofs etc.. 150A 3phase jobbies...

 

[securespark]

don't forget that an air con will need a C or D type breaker because of the starting currents..

I have NEVER seen an air conditioner on a D breaker. Most I have seen on C's, mine at home is on the ring main, on a B32 - its 2kw.

The fact is most quality air conditioners will cope on a B breaker.

As long as the loop is low enough, it shouldn't be a problem.

 

[Stoday]

These days air conditioners have soft start gear, so will work happily with B type MCBs. They don't cause voltage dips like the old ones did either.

 

[r.bartlett]

Don't mix duty with load. A 3.5kw duty inverter air con will pull 4 amps max these days full load but start at around 1a..Even the old DOL units will happliy live on a 13a fused spur.

Cheers

Richard