Power supply for domestic air conditioning split system

[holmslaw]

..

 

[JohnW2]

I would personally have thought it wise to have RCD protection for an item of electrical equipment that could possibly fill up with rain water.

It's unwise to have any mains power in contact with water.

Exactly, so if there is a potential risk of it coming into contact with water, it would seem wise to have something in place that will disconnect the supply should that situation arise.

Kind Regards, John.

 

[slup]

But surely just about every air conditioning unit in any country where it may ever rain is at risk of being exposed to water?

And I bet less than a fraction of a fraction of them are on RCD protected supplies because they don't need to be.

What is the risk that you perceive?

 

[bernardgreen]

How large is tne motor in this unit ?

Any motors larger than 1 Kw are considered as "disturbing loads" by the Distribution Network Operator and I believe have to be notified to the DNO.

The application for a new supply I have just completed required notification of motors greater than 1 Kw as well as any welding equipment that might be used on the supply.

 

[SimonH2]

How large is tne motor in this unit ?

Any motors larger than 1 Kw are considered as "disturbing loads" by the Distribution Network Operator and I believe have to be notified to the DNO.

The application for a new supply I have just completed required notification of motors greater than 1 Kw as well as any welding equipment that might be used on the supply.

Really
There must be an awful lot of DIYers with loads such as that that have never notified anything, is it a new requirement ? I guess I'd better keep quiet about the 3hp pressure washer, 3hp compressor (nearly had a 4hp but not enough room for it), various other machines, stick welder, MIG welder .. and my mates MIG welder that really could do with a 32A supply (we just keep it turned down, on full it can take over 40A I believe).

Back to the OPs queries though.
Mention of FCUs and chasing out makes me wonder ...
Has the OP checked the requirements ? It sounds like he's putting supplies in for the indoor units, while all the split systems I've had any dealings with have had a single supply to the outdoor unit, and the indoor units have been supplied from that - with the data sharing the mains cable.
If that's the case, then as well as the main supply cable, there'll be one (or possibly 2) power/data cable from the outdoor unit to the indoor units. The normal route for these would be with the pipes, and since I've yet to see an A/C installer chase out a wall, I'd assume the cable would go in the trunking they'll use between ceiling and indoor unit.

 

[Stoday]

There must be an awful lot of DIYers with loads such as that that have never notified anything, is it a new requirement ? I guess I'd better keep quiet about the 3hp pressure washer, 3hp compressor (nearly had a 4hp but not enough room for it), various other machines, stick welder, MIG welder .. and my mates MIG welder that really could do with a 32A supply (we just keep it turned down, on full it can take over 40A I believe).

When you or whoever originally applied for a connection to the DNO's distribution system, you declared what load you would want. The connection would then be provided to cater for that load. If you want to add additional load, you should ask to redeclare your load requirement. If you're unlucky some jobsworth will get hold of your request and charge you an arm and a leg to modify your connection.

An alternative is to add your load and keep schtum. You'll only run into a problem if a nearby consumer complains about his flickering lights. Then you'll have the option of disconnecting your new load or paying for the connection augmentation.

 

[SimonH2]

When you or whoever originally applied for a connection to the DNO's distribution system, you declared what load you would want. The connection would then be provided to cater for that load. If you want to add additional load, you should ask to redeclare your load requirement. If you're unlucky some jobsworth will get hold of your request and charge you an arm and a leg to modify your connection.

Well we've never applied for a connection - it's been there when we moved in. We never go anywhere near the limit of the supply fuse (100A)
^ That's a wink in case you missed it !

An alternative is to add your load and keep schtum. You'll only run into a problem if a nearby consumer complains about his flickering lights.

You mean they'll do anything about that - a friend of mine has suffered from flickering lights for years and they won't do anything. Mind you, it's not local users causing it - no idea what is, but it's there all the time. All they'll do is plug a monitor in, declare the mains to be within spec, and leave. Done it for years, and IIRC (it's some time since he told me) it affects several houses in the street.

 

[ban-all-sheds]

All the people affected should band together and implement flickering bill payments until it's sorted.

 

[martinxxxxxx]

The big black sticker on the fuse board answers your questions. I would of preferred if it said "Electrical equipment outside of the property".

Why would a permanently fixed air conditioning unit fed by SWA cable need an RCD? The fact that it is outside is irrelevant?

and good luck terminating the SWA into that fuseboard. I know it sound sarcastic and you're trying to save money, but really it is worth doing a good job rather than some old bodge up. Which in my opinion would be the case if you do anything other than change that board. By the way the picture is not clear but is that a wooden back construction board and is the total rating only 60Amp.
This is you home that you are obviously planning to stay in for a while, so don't penny pinch on safety Get it done right. How much is the split system costing

 

[slup]

I wasn't commenting on the suitability of the original posters consumer unit - I was questioning the assertion that the circuit needed to be RCD protected.

 

[r.bartlett]

Hi

I will shortly be purchasing a split system with 1x outside unit and 2x inside units for my house (domestic).

The aircon company will do the refrigerant circuits and want the electrical circuits ready for when they arrive.

I will do as much of this as possible as well as employ a sparks and have some questions please.

Q1. For the external aircon unit I will need a separate circuit rated to 20A. My consumer unit is the old type with cartridge fuses. Do I need to upgrade the CU to a 17th edition complaint one with MCBs? If so I would get the sparks to do this!

Q2. Re. cable to external aircon unit, can I install Hi-Tuf or does it have to be SWA? I was going to use cleats to fix to outside of brick wall. Is this OK or do I need to use conduit and if so what spec please?

Q3. I did the Vd and EFLI calcs and 2.5sqmm will be fine however for belt and braces I will install 4sqmm. I was planning on doing the donkey work (routing the cable thru the walls) and leave the sparks to terminate the cable in the isolator/CU. Am I allowed to do this in terms of building regs?

Q4. Re. inside aircon units, I was advised by aircon firm that these units can be run off ring main circuits provided FCUs are used. Am I allowed to do this in terms of building regs? I've spurred off bedroom sockets in the past but never really knew if I was allowed to do it!

Thanks!!

PB

What system are you having as most if not all are fed to the outside and the interconnect powers the inside. Is this an inverter system ?