220V Air Conditioner: How Far of a Run?

It sounds like you need to get hold of a professional engineer or technician to help you....

Something like this and with your possible lack of understanding could be dangerous to advise on...

Best to get local professional advice methinks...

John.

I'd have thought it would have a wattage or current rating on it somewhere? Without that you are in the realms of guesswork...and if you are not confident/competent to measure the current consumption yourself, I'd take Electroman's advice.

Current CE regs in Europe state any electrical equipment must have voltage/wattage(or current) frequency etc clearly labelled.... surely it's similar over there?

Maybe have a look at the fuse rating that will give a clue... but not conclusive...

Good luck

Del.

netmaker,

You have incomplete data, however we can only assume.The 25000 btu should be 25000 btu/hr which roughly equals 2 hp ac unit with an ampere rating of about 12A. It can be fed by a 220v ,1 ph, 60hz source. The 30"/3 prong probably refers to the length of the cord and the plug configuration attached to the ac unit.

if your load(acu) is located not too far say, less than 50 feet, then 3/c- #12 AWG THWN/THHN, or THW insulation would be sufficient to compensate the drop in voltage.The 3c - #10AWG can go even as far as 100 feet.

i would also assume that your generator is the portable type with a 4 prong male plug attached to it. i suggest that you contact a registered electrician to perform your wiring connections.

We'll start with this. If your plug has one horizontal blade and one vertical blade and one round (ground) blade, your electrical connector is rated 20 amps.

The Neutralis not used in this application. The ground must be hooked up.

To elaborate on my answer; Since the AC unit has a three prong plug, The ground (round or Semi round prong) is an equipment ground only. It is not a current carrying conductor, except in fault conditions. Therefore it is not required to be an insulated conductor. You can actually use 12/2 or 10/2 NMB, or UF Cable. (12/3, or 10/3 SJ, or SO Type Cable.) My point is you only need 3 conductors. If 4 conductor wire is used the ground from the device must be bonded with the box in the event a metallic box is used. The insulated (white ) neutral should be capped off. (unused.)

If a female plug end is used I would recommend only using three conductor cable anyway.

Can you get nameplate data off your AC? Or a model number? If so, the FLA should be on the nameplate or maybe it can be found on the internet. With that info, I can give maximum distance that your wire length is to be to provide voltage to your AC allowing for voltage drop.

To All,

I found I have a 20 amp, 220v AC unit.

I also know what to do with either a 10/2, 10/3 or 12/3 wire to make the connection to the Generator set ( how to wire the male and female plugs).

Now, all I need to know is;

which of these wires can I run 15' to complete the connection: 10/2, 10/3 or 12/3

Thank you. netmaker

12/3 is all that is required. (20 amp)

12/3 it is.

Connections made and gen set runs everything as expected..........

........now we are ready again for whatever the season brings us, which I hope is no more than a rain squall!

Thanks to all.

netmaker

Please NOTE; In the USA the cord cap that you described is a 110-120 vac plug. Not a 208-220vac plug. If both blades were horizontal then it would be a 208-220vac plug.

One side of the plug has horizontal flat blade Just makes it a 20amp cord cap. This is to prevent you from inserting it into a 110-120vac 15 amp receptacle and overloading the circuit.

one vertical flat blade 110-120vac

and one round (ground) prong

If the run is in conduit I would pull the extra ungrounded conductor out, be sure to bond all of the metallic portions (including any switches and receptacles) of the raceways, boxes, and devices with the ground wire (green).

If cost is not an issue I would use #10 wire as it has a less resistance and a better ability to dissipate heat (but #12 will suffice).

The ungrounded conductor (the wire coming off of the breaker) hooks up to the brass color screw. The white conductor (by code if smaller than #6 must be white or gray) goes to the white screw, even though the neutral is known as the grounded conductor it should not be hooked up to ground at any point in the circuit, but should go to the panel neutral bus bar (at the panel box where the service first enters the house the neutral bus bar will be bonded to ground) . If you only have one Panel Box then you may just have one common bus-bar (with white, green, or bare conductors on them).

BTW; I am an electrical inspector for a larger county in California (so thats what I would expect to see).

As far as length of run if you are going less than a hundred feet the voltage drop would be insignificant.