Power requirements for air-con

Interesting bits:

Fuse Rating (BS88) - HRC (A) 16 Starting Current (A) 27 Running Current (A) - Heating / Cooling 4.34 / 4.65

There's another 40W for the indoor unit, but I think that can be ignored...

Andy

Thanks Andy - it's looking like the starting current is a (very large) typo, and should be somewhere around 5-6 amps. This is line with other similar units on the Mitsubishi web site.

Midge.

Starting current is very believable for an induction motor compressor. If mine tries to start with a locked rotor (as happens with compressors if they try starting too soon after they switched off and there's still a pressure differnce across them), it draws over 4kW (limit of my power meter), but not for long enough to blow the 13A fuse before it realises, and then it waits a bit before trying again.

The starting current figure isn't always shown on the specs I've found - but where it is, there is further evidence to support the 27A startup figure (much lower figure given by my air-con fitter over the phone) so looks like you're right Andrew.

The breaker currently fitted is a type B 16A and my understanding is that shouldn't trip with this sort of startup current (earlier thread suggested a type C may be needed). Any thoughts/experiences on that?

Out of curiosity, how does the startup current on a motor stack up against the rating of the cable? I think my single 2.5mm has a rating of 27A anyway (clipped, not in conduit) so isn't a problem - but what sort of peak current can a cable take above its continuous rating?

TIA Midge.

My understanding is that the rating is mostly to control heating of the cable - which tends to be hidden away where you wouldn't see it.

Andy