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Discussion Starter #1 (Edited)
Hi Experts,
Attached is a plate attached to an air handler for an HVAC system. The first arrow shows 208/230 volts, while the second arrow shows 120 V. Currently, the breaker that the wire from the air handler is connected to is a double pole 30 Amp. The wire is 10 guage with one black wire connected to one side of the breaker, one white wire connected to the other side of the breaker and one ground wire connected to the ground bar. So there are two hots and no neutral connection. Is this unit 120 V or 240 V? Is there any thing wrong with the wiring and the breaker arrangement? Does it matter whether the breaker is 30 A or 15 A? Thank you.

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Each leg of a 220 V system will go to ground as 120v. They are saying not to exceed 120 at each line.

If you got nothing added to the unit then it looks like you need 208/230 volts on a 15 amp breaker.
 

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Discussion Starter #5
The breaker is currently wired as 120V with the white wire connected to the neutral bar and the breaker is OFF. Seems like it should be wired as 240V with the white wire connected to the second pole of the breaker and no neutral connection. Is that correct?
 

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I’m not an electrician, but i think your breaker is too big ... should be a double 15. In the box of info between the two arrows, there is a line that says “max overcur protection 15A”.
 

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The breaker is currently wired as 120V with the white wire connected to the neutral bar and the breaker is OFF. Seems like it should be wired as 240V with the white wire connected to the second pole of the breaker and no neutral connection. Is that correct?
That would be correct according to that nameplate. Breaker should be a 2-pole 15A.
 

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The breaker is currently wired as 120V with the white wire connected to the neutral bar and the breaker is OFF. Seems like it should be wired as 240V with the white wire connected to the second pole of the breaker and no neutral connection. Is that correct?
Wait, what?? What do you mean the "breaker is currently wired as 120V with the white wire connected to the neutral bar"?

I'm not entirely sure what you've got going on, but if you have a white wire going from one side of that breaker to the neutral bar, and you flip on the breaker, your breaker is probably going to explode in your face. I'm guessing I am just misunderstanding what you've got going on, but you never know.

Others have given you good info so far. You (or maybe better yet an electrician) need(s) to change that breaker to a 15A double pole. This is only for the blower, if that air handler also has electric heat then you might need an additional breaker and circuit to handle the heating load.

On a 230V circuit you really shouldn't use white wire. It would be best (and code) to remove the white wire and replace it with another black or a red wire. At a minimum, you should either color as much of it as you can with a sharpie or wrap it tight with black electrical tape.

Oh, and you are correct, with a straight 230V circuit like you've got there, you do not need a neutral wire.
 

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Please take another picture showing the wiring to that breaker.
Can't tell much from that close up.
The motor requires a two pole breaker, 15 amp as others have mentioned.
But if you do have resistance heat installed in that air handler that information should have been added.
What size wire do you have going to the air handler?
I'll guess that's a heat pump?
 

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The 'heat pack' kit the label mentions is likely present - perhaps 4kW or so.

My heat pump had a 4kW and 30A breaker on #10. Later I upgraded it to 9kW which required a 60A breaker and #6.
 

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When they say "120V to ground" they mean the 230V must be 2 hots with a center ground. They are prohibiting a couple of things:

- Wiring it up hot-and-neutral from the orange leg of a wild-leg 240V delta system (which has 3 phases, two of them 120V from ground, the third 208V from ground).

- Taking it to Europe and running it off 230V single-phase which has neutral and 1 phase that's 230V from ground.
 

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I am a bit confused with the name plate, 208 v where I live is 3 phase. No taking 2 legs of the 3 phase does not get you 208. 230/240 is a common single phase voltage. Which number you use is more regional than anything else. Where I live 240 is the correct number. The reference to the 120 volts is for a motor heater which with any luck you do not need and do not have. Ignore this unless you have one.

Motors should be protected by no more than 150% of the name plate full amp draw. So your more like 10 amps. 30 will work and it will allow > 3 times the energy in when there is a problem so that for sure there will be a lot of magic let out of the circuits. 10 amp breakers are hard to find, So get a manual motor started with one over load, sized correctly to protect the motor
First one on the search I did. Provided in case your not familiar with them
Breakers are not installed to protect equipment, they protect the wire. A 30 amp breaker should have 10 gauge
White wires are not limited to the grounded conductor work in residential. They can are are used as current carrying conductors.
Be safe
 

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Any 2 legs of a 120/208V 3Ø service will give you 208V. The nameplate indicates it is acceptable to run the equipment at that voltage.

Nameplate also indicated the motor is electronically protected. No need for a manual motor starter.

Nameplate indicates a minimum of 15A supply conductors. #10 meets that requirement.

Nameplate indicates a maximum of 15A overcurrent protection. Breaker has to be changed to 2 pole 15A.
 

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I am a bit confused with the name plate, 208 v where I live is 3 phase. No taking 2 legs of the 3 phase does not get you 208. 230/240 is a common single phase voltage. Which number you use is more regional than anything else. Where I live 240 is the correct number. The reference to the 120 volts is for a motor heater which with any luck you do not need and do not have. Ignore this unless you have one.
You are incorrect on pretty much all of the quoted stuff above.

IF you have 208V 3 phase, taking 2 legs of that power will give you 208V. I've never seen a volt meter with 3 leads, don't know how you expect to check voltage on all 3 legs at the same time. Just trust me on this, 208V 3 phase will give you 208V between any 2 of the 3 wires.

230V 3 phase is around, usually in older parts of the city. This is kind of an oddball service since one of these legs to ground/neutral will measure 208V, but this 208V can't be used for anything. If you want 230V single phase you can use this oddball leg with one of the other legs (or any combination of 2 of the 3 legs) and you will get 230V. It's only if you are trying to get 120V where this oddball 208V to ground leg comes into play, and then you need to avoid it.

Also, the part where you said "The reference to the 120 volts is for a motor heater" is incorrect as well. As was stated by a few people, the reference to 120V is just as the sticker says, "Max voltage to ground of supply circuit...". That means L1 to ground and/or L2 to ground should be less than 120V. The warning is referring to the situation above where one leg of 230V 3 phase will give you 208V to ground. The sticker is telling you that you need to avoid that leg.

You are correct that I think this warning only applies if you have the optional heat kit, which the OP might not have, so either way he can probably ignore it.
 

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We're talking about 2 quite different things.

208V 3-phase "wye", which gives 3 phases of 120V. Just the thing for an apartment building.



In 208 "wye", all 3 phases are 120V away from neutral and ground. You can connect a load between any 2 phases and get 208V, or connect it to all 3 phases (with no neutral) and get 208V "delta" (sorta).





The other thing we're looking at is 240V "delta" with a modification to place neutral/ground halfway down one leg of the "delta", so that leg looks like a 120/240V split-phase system.



You can put 240V loads on any side (any 2 corners), 240V "Delta" loads on all 3 corners, 120V loads on either half of the bottom side, and then you have this wacky leftover thing between phase B and neutral/ground, that is 208V, but not all that useful. As I said, the appliance's instructions are saying "don't use that because the wild leg is over 120V from ground".

By the way, if someone uses a rotary or electronic phase converter to take 120/240V service and "manufacture" that third phase B, that will come out as "wild leg".
 

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Nameplate indicates a maximum of 15A overcurrent protection. Breaker has to be changed to 2 pole 15A.
As I mentioned before with the heat pack... an air-handler may be manufactured/ordered without it, but one may be fitted at the time of install. (i.e. approved electric heater accessory.) In this case the original nameplate is no longer correct.

If the OP cannot make an educated assessment of this possibility, he should get an HVAC tech or Electrician to do so.
 

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I am a bit confused with the name plate, 208 v where I live is 3 phase. No taking 2 legs of the 3 phase does not get you 208. 230/240 is a common single phase voltage. Which number you use is more regional than anything else. Where I live 240 is the correct number. The reference to the 120 volts is for a motor heater which with any luck you do not need and do not have. Ignore this unless you have one.

Motors should be protected by no more than 150% of the name plate full amp draw. So your more like 10 amps. 30 will work and it will allow > 3 times the energy in when there is a problem so that for sure there will be a lot of magic let out of the circuits. 10 amp breakers are hard to find, So get a manual motor started with one over load, sized correctly to protect the motor
First one on the search I did. Provided in case your not familiar with them
Breakers are not installed to protect equipment, they protect the wire. A 30 amp breaker should have 10 gauge
White wires are not limited to the grounded conductor work in residential. They can are are used as current carrying conductors.
Be safe
“Motor heater”?

I’ve seen heaters in motors when condensation is an issue, but never in a furnace’s motor. Maybe you’re talking about a crank case heater? Those are located in the outdoor unit at the compressor... different data tag.
 

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Discussion Starter #20
The breaker has been changed to 15 amp double pole. The wire from the breaker to a disconnect near the air handler is 10 gauge (orange). The wire from the disconnect to the air handler is 12 gauge (yellow). And yes, I used the 10 gauge wire from the breaker just for the possibility that I may add a heating element in the future. There is no heating element now. I will take a picture of the 15 amp double pole breaker and upload it tomorrow.
 
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