# AC mini split typical load? Sizing service upgrade



## cl2sparky (Jan 3, 2017)

mikewillnot said:


> Sizing a service upgrade, smallish suburban house with an EV coming (NEMA 14-50 continuous load); customer says "I may be adding a couple of mini-split air conditioning units down the road." No details, specs, nothing. Anyone know anything about the range of possible loads for these kind of units?


The one I have done were 20A 2-pole. 


Sent from my 1911-A1


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## HackWork (Oct 2, 2009)

Mini splits are usually pretty efficient.

With the complete lack of info, I'd say just throw up a 200A service as long as heat, hot water, dryer, and range are natural gas. If those items are electric, you are going to have to do more digging.


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## Glock23gp (Mar 10, 2014)

20 amp 240 volt circuits for most residential and small commercial.

There are larger ones but I have only wired a 12-2 to an outside disco.


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## telsa (May 22, 2015)

HackWork said:


> Mini splits are usually pretty efficient.
> 
> With the complete lack of info, I'd say just throw up a 200A service as long as heat, hot water, dryer, and range are natural gas. If those items are electric, you are going to have to do more digging.


EVs -- in some areas -- can be recharged at night for a reduced expense. This is a Poco by Poco decision, so you'll have to check around. ( This is a repeat of the late-hours hot water scheme we all know and love.)

If this is the case, it absolutely affects your load calculation, for the recharger will only fire up when most all other loads are off. 

As for mini-splits, the fact that they have separate condensers and evaporators is irrelevant from a load point of view. Figure on 20A at 120VAC*http://www.electriciantalk.com/member.php?u=85514* for each 1.5 tons of refrigeration capacity.

Your real load worry is if they're actually intending to install a heat pump. These will usually come with all electric booster coils - for cold snaps like we're experiencing right now.

It's those puppies that suck down the Watts -- and how!

Booster coils are normally field installed -- or, if factory installed, priced as a semi-custom extra. Every last heat pump I've ever touched has the ability to accept 0, 1, or 2 boosters. You may find the heat pump installed without its booster -- and come back to find that the HVAC dudes tossed one in. (It was flown in by Fedex.)

All of which is a long way to say that you need feed-back from the HVAC boys to know what's typical in your area. In my town, one booster is sufficient -- and necessary. Hawaii doesn't need any booster. Iowa figures to need two, and so forth. 

The rise of EVs and heat pumps must make electricians put their thinking caps on -- load calc wise.


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## mikewillnot (Apr 2, 2013)

HackWork said:


> I'd say just throw up a 200A service


There's a decent 150-amp panel there now, on a 100-amp riser/meter setup.  I told them it might be OK to upgrade everything but the panel, to a 150, but that a 200 might be necessary or strongly advisable. The AC thing tips the scales, I think.


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## HackWork (Oct 2, 2009)

If this is just a small house, I could see 2, maybe 3 9,000 btu mini splits which generally run off a 15a 120v circuit. So 150A may be enough even with the EV.

We are all just guessing.


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## mikewillnot (Apr 2, 2013)

telsa said:


> Your real load worry is if they're actually intending to install a heat pump. These will usually come with all electric booster coils - for cold snaps like we're experiencing right now.
> 
> It's those puppies that suck down the Watts -- and how!


Very helpful. THANKS


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## oliquir (Jan 13, 2011)

a 2-20amp will be good for the bigger ones, my 15k btu only use 2-15A and my last 12k btu was 120v 15A


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## wildleg (Apr 12, 2009)

https://www.ajmadison.com/cgi-bin/ajmadison/LS300HLV.html


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## MechanicalDVR (Dec 29, 2007)

oliquir said:


> a 2-20amp will be good for the bigger ones, my 15k btu only use 2-15A and my last 12k btu was 120v 15A


For estimating futures it's better to figure for higher than lower and be wrong.

2 pole 20s is a safe bet.


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## frenchelectrican (Mar 15, 2007)

It is very common in my island area.

Here a quick run down for mini split units .,,

small resdentail units typically use on 10 or 15 Amp 240 volt circuit.

Ditto with small commercal units.

Med to large mini splits .,, that depending on size and phase. ( useally 20 amp or higher )

Pay attetion to disconnecting means due majory of time the disconnection useally on outdoor side. the indoor you can add a switch however it depending on model and number of conductors going to indoor unit. 

Note : we only have 240 volts line to neutal system on resdentails.


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