Subpanel for heatpump and water heater

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Old 02-08-14, 02:48 PM
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Subpanel for heatpump and water heater

I am out of space on my main panel, so I am planning to install a sub panel.
But my panel is in one corner of a finished space in the basement. I'm wondering if I can install the sub panel next to the heatpump air handler in an unfinished part of the basement. What I want to do (if possible) is use the wire running from the panel to the air handler as the wire to the subpanel and then install a breaker in the subpanel for the airhandler. In addition I can then move the water heater to the subpanel too. This would free up space for a 220v mini split in the main panel.

The airhandler is on a 60A and 30A breakers and the water heater is on 30A.

Assuming the wire gauge is sufficient, can a 60A subpanel be installed and would it be sufficient for the airhandler, water heater and smaller stuff in future?

Reason I want to do this is a subpanel in unfinished space would allow me to get to it from whatever appliance I want to hook up whereas the main panel is very isolated and completely drywalled.

I would still get an electrician, just want to know my options before talking to him/them
 
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Old 02-08-14, 02:51 PM
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The feeder for the air handler is sized just for the unit. It also does not have a neutral you need for the sub panel.
 
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Old 02-08-14, 07:39 PM
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The airhandler is on a 60A and 30A breakers and the water heater is on 30A.

Assuming the wire gauge is sufficient, can a 60A subpanel be installed and would it be sufficient for the airhandler, water heater and smaller stuff in future?
The airhandler is a two circuit piece of equipment and probably is just a 15 KW electric furnace. Not only do you not have a neutral for smaller stuff, but you cannot use the two circuits in parallel to feed a subpanel. Even if you could use those two circuits to a subpanel, you still don't have enough capacity for the water heater to be added to it.
 
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Old 02-09-14, 09:57 AM
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OK - makes sense. I was just hoping, but didn't really think it possible.
Correct - it is a 15kw backup heatstrip. I have always wondered how those are sized.

But let me change track and ask if I can make space in my current panel for the mini split (220v 15A breaker).

Here are pictures of the panel filled as is and the panel info.

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Old 02-09-14, 10:17 AM
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It does not look like you can fit another tandem in the panel let alone a two pole too feed a sub panel. Some circuits will need to be moved to a subpanel to make the room needed.
 
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Old 02-09-14, 10:21 AM
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ask if I can make space in my current panel for the mini split
I count 28 spaces used and your model number, G2040mB12, indicates 40 spaces available so you could replace two full size breakers with tandems and move two additional 120 full size breaker loads to two of the tandems to allow space for a full size 240 breaker. Assumes permitted spaces for tandems are not all in use for tandems already. That I'll leave to the pros to answer.
 
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Old 02-09-14, 10:26 AM
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The trouble is that the two poles are using the space of 4 tandems. I don't see how another tandem can be added.
 
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Old 02-09-14, 12:04 PM
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You can free up additional space by replacing two 30A 2 Pole breakers with one quad like this one.

30/30 Amp 3-1/2 in. Double-Pole SIE Quad Circuit Breaker-Q23030CT2 at The Home Depot

Also by replacing full sized single pole breakers with tandems. The tandems and quads should fit anywhere in the panel since it is a 20-40 panel.
 
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Old 02-10-14, 06:41 AM
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This is interesting, I did not know something like this existed. Why could I not install one of these quad Breakers in place of an existing 30a breaker and hook the mini split up to that in addition to whatever is on that breaker originally? The mini split only requires 15a but surely as long as complying to the code wire requirements I should be fine?
 
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Old 02-10-14, 07:08 AM
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With the exception of GE which uses half breakers tandems for most panels are 120v only because they both connect to the same bus bar. Joe's solution of a quad is much more elegant then mine because it requires only the removal of two side by side full size 120 volt breakers.
 
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Old 02-10-14, 08:21 AM
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Sorry Ray, but your answer confuses me. Is the one set of poles 240 and the other 120?.
 
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Old 02-10-14, 08:45 AM
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Sorry Ray, but your answer confuses me. Is the one set of poles 240 and the other 120?.
They can be depending on which quad breaker you choose. The ones I see mostly are two 2 poles, but some are one 2 pole and two single poles. I'll see what I can find.

Here is one that has combined a 30 amp 2 pole and a 20 amp 2 pole in a quad breaker. You could replace an existing 30 amp 2 pole breaker with this and install 12-2 NM-B cable from the 20 amp 2 pole to a 30 amp fusible disconnect at the mini split and fuse it at 15 amps.

30 Amp / 20 Amp 2-Pole Sie Quad Breaker-Q23020CT2 at The Home Depot
 
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Old 02-10-14, 11:11 AM
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Something like this?
GE 30 Amp 120/240-Volt 240-Watt Fused AC Disconnect-TF30RCP at The Home Depot

I cannot find info on if it takes 15amp fuse. BTW not sure why it must be 15a
 
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Old 02-10-14, 02:03 PM
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Unless the instructions call for fuses all you need is a pullout disconnect for the mini split.
 
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Old 02-10-14, 04:46 PM
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I read through the install manual again - It does not call for a fused disconnect. It does not even call for a disconnect, but I will install one.
Specifications are as follows:
Circuit Breaker - 15A ("Use a circuit breaker or time delay fuse")
Power supply cable - 208/230V AWG_"A" GN/YL 14
Connecting cable between indoor & outdoor - 208/230V AWG_"B" 18

So I will use 12-2 from the breaker to the disconnect. Some of this will be outside - do I need to get a specific cable or conduit?

And 14-4 between inside/outside

I will get a basic 60A disconnect and 6-12-6NM whip

And then the breaker linked earlier. Anything I'm missing? I assume this breaker will work in my panel?
 
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Old 02-10-14, 05:07 PM
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The breaker needs to match the panel. The label inside the panel will have the correct types that can be used.
 
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Old 02-10-14, 05:53 PM
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Some of this will be outside - do I need to get a specific cable or conduit?
NM-b can not be used in wet locations, Conduit outside is a wet location. You could use UF-b cable in PVC conduit but it is hard to pull. Best practice is individual THWN wires.
 
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Old 02-10-14, 06:07 PM
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Panel requires Gould ITE Type. The specs on Amazon shows it as Siemens/Gould ITE Type. So good there.
 
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Old 02-10-14, 06:10 PM
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NM-b can not be used in wet locations, Conduit outside is a wet location. You could use UF-b cable in PVC conduit but it is hard to pull. Best practice is individual THWN wires.
I was thinking of using UF-B. Do I need to put it in a conduit. I see my current central air condenser is wired up just in the jacket, no conduit
 
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Old 02-10-14, 07:10 PM
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UF-b must be protected. It sounds like your AC isn't wired in a code compliant way. An exception would be if it was too high to be easily damaged.
 
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Old 02-10-14, 07:47 PM
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Physical damage is not defined by the code. It is up to individual interpretation. Whether the UF needs to be protected is a judgment call.
 
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Old 02-10-14, 08:16 PM
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I read through the install manual again - It does not call for a fused disconnect. It does not even call for a disconnect,
You need a disconnect. I just suggested a disconnect fused at 15 amps to match the specs you stated earlier in the thread for protection of the circuit, but all I found was a quad that had 20 amp capability.
 
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Old 02-11-14, 06:01 AM
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Joe, thanks for the help you saved me some serious cash. I will have to contribute to your beer fund!
I will definitely install a disconnect. I was more wondering about the logic for the fuse size. Thanks for clarifying.

I have ordered the parts and am ready to do the install.
 
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Old 02-11-14, 06:24 AM
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I have ordered the parts and am ready to do the install.
........................................
 
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Old 02-15-14, 04:54 AM
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I'm back with one more question
After I ordered the parts I started wondering if I want to do some future proofing in case I ever go to a larger a/c unit. Some call for 25 or 30 amps.

Can I install a 30 amp breaker and 10-2 wiring for this 15 amp unit? I did some digging on the Web but could not find a definitive answer. Thanks!
 
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Old 02-15-14, 05:09 AM
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Most likely you may not run a 30 ampere feed directly to the 15 ampere air conditioner without a subpanel (or sub-subpanel) with 15 amp breaker in between. The AC unit has a maximum branch circuit rating which is probably 20 amps. This should be stated on a nameplate on the AC unit or in the instructions.

Alternatively if the AC unit is a plug-in unit, the plug implies the maximum branch circuit rating such as 20 amps or 30 amps.

You may install the 10-2 feed now but connect it to a 15 amp breaker pair. In the future you could upgrade to a 30 amp AC unit and up the breaker to 30 amps (and change out the receptacle at the AC unit to be 30 amps if applicable).

* Sub-subpanel is not a recognized electrical term. Subpanels may be fed by other subpanels.
 

Last edited by AllanJ; 02-15-14 at 05:26 AM.
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Old 02-15-14, 06:00 AM
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Thanks for the response. You would have to read the whole thread to realize I am not going with a subpanel anymore. I will use a speciality breaker and the smallest I can get that breaker in is 20amp.
 
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Old 02-15-14, 07:25 AM
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It looks like a couple of the breakers are double-tapped. (red wires and others). You should clean this up. Also GE breakers which are probably not rated for that panel.
 
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Old 02-15-14, 07:55 AM
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Even for a 30 amp AC you could probably run #12. The sizing rules are different for HVAC.
 
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Old 02-15-14, 09:53 AM
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Can I install a 30 amp breaker and 10-2 wiring for this 15 amp unit? I did some digging on the Web but could not find a definitive answer.
Yes, you can install a 30 amp breaker and 10-2 NM-B cable, but you would still need the 30 amp fusible disconnect fused at 15 amps ahead of the mini-split.

pcboss

Even for a 30 amp AC you could probably run #12. The sizing rules are different for HVAC.
PCboss brings up a good point, but the bottom line is it all depends on the specific unit and you have no idea at this point what it would be.
 
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Old 02-15-14, 12:34 PM
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@ CasualJoe - so if I understand correctly, the reason for the fuse is to provide over-current protection so that the fuse would blow before the 30 amp max is exceeded and the breaker trips?

@ Astuff - yeah, I'm planning to replace the GE breaker with the quad breaker discussed in this thread. There's a few Bryant breakers I want to replace too. Whoever finished the basement for the previous owner did a real hack job of the electrical stuff.
 
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Old 02-15-14, 06:27 PM
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@ CasualJoe - so if I understand correctly, the reason for the fuse is to provide over-current protection so that the fuse would blow before the 30 amp max is exceeded and the breaker trips?
Yes, earlier in the thread you stated the mini-split needed to be protected at 15 amps. Just curious, who is the manufacturer of the mini-split heat pump. I have an application for one, but haven't made a definite decision on it yet.
 
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Old 02-16-14, 09:49 AM
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It's an LG. Some manufacturers like Mitsubishi and Fujitsu don't allow sales from unauthorized dealers (ie Web dealers, thus have to buy from installers or non discounted prices from Hvac suppliers). As long as the LG is installed by a licensed tech the warranty is good. I think Panasonic (prev Sanyo) is the same. Not sure about Samsung or Daikin (not commonly available in usa). These are most of the top brands, not looking at bargain brands as they are not that much cheaper.
But realistically the warranties exclude labor, so do you really want to pay that much more to have a parts only warranty?

Perhaps more than you wanted to know, but I have spent significant time investigating. Mitsubishi is the most popular in us with Fujitsu in second place. But this is perhaps mostly based on time in market. In other countries Samsung is considered best. I think compare on seer, features, warranty length (whether you use it or not) and price.
Oh, and lastly, get an inverter model!
 
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Old 02-16-14, 12:10 PM
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Perhaps more than you wanted to know, but I have spent significant time investigating. Mitsubishi is the most popular in us with Fujitsu in second place. But this is perhaps mostly based on time in market. In other countries Samsung is considered best. I think compare on seer, features, warranty length (whether you use it or not) and price.
Oh, and lastly, get an inverter model!


No, not at all more than I wanted to know in fact, I have more questions. I have noticed that the units I have investigated never seem to have any electric resistance backup heat built into them. I have also read that these mini-split heat pumps will continue to heat down to around 0 degrees F so backup heat is not always necessary. What does your investigation tell you, will they continue heating down to 0 F outside air temperature? I also noticed that Luxaire has a mini-split, do you know anything about it?
 
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Old 02-16-14, 01:43 PM
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Mine is rated -4 and there are units that go slightly lower, but yes around zero is the norm. There is a website greenbuildingadvisor dot com. And many of the contributors on that website are from the north-eastern part of the country and there are many blog entries and featured homes on the site being only heated/cooled by mini-splits. So it seems they can go down to the rated temps and more. As I understand it, they put out their specified heat up to the minimum temp. Below the min temp they still work, just at lower output and probably efficiency. But it is also a factor of how well the house is insulated and how tight the building is. My house (aka wind tunnel) is not very tight hence why I want to supplement my under-spec'd heatpump with a mini split. But I live in DC and it rarely gets that cold here, so it is is not a major factor for me.

Here's a link to the first example I could find. Perusing the site will yield many more
Just Two Minisplits Heat and Cool the Whole House | GreenBuildingAdvisor.com

Not at all familiar with Luxaire. Sorry.
 
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Old 02-16-14, 06:37 PM
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I believe I happened upon that website once before and found it very informative. Thanks for the info.
 
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