E Heat circuit breaker getting hot?

[reader2580]

Couldn’t those two smaller red and black jumper wires be removed as a temporary fix? The house may not be as warm as desired, but the circuit won’t be running right at breaker capacity anymore.

 

[mm08822]

So what jumper can he pull to get this back to "normal"?

Note: I'm not sure if the wire/breaker combo is adequate even with the jumper(s) removed

The red and black jumpers supplying the second fuse blocks powers the third heater element. Pull those and 1/3 of the load is gone. Maybe the house starts to get cold if they were needed b/c 2 banks couldn't keep up.

Ahh, yeah, since the heater is only on #8 NMB, that was FUBAR from day one. Should have been #6. Somebody screwed up the install.

 

[600SL]

So what jumper can he pull to get this back to "normal"?

Note: I'm not sure if the wire/breaker combo is adequate even with the jumper(s) removed

It looks like I have found two circuits that I can remove from the main breaker box that can be use to add another 25a 2 pole circuit. I believe I could remove the two jumpers and connect the 25a line up to the smaller set of fuses. That would mean no breaker panel.

 

[Bert_]

Try pulling the small fuses out. That will drop the heater to 10kw. See if it is able to maintain temperature.

If 10kw is adequate you could stay with a single 60A circuit. Simple, done.

No idea if yours is but many furnaces/heat kits are substantially oversized.

 

[mm08822]

Normally for such circuits the load would be below 55a. Its only in this case that it happens to be 60a because someone f up. But if I go with two circuit system I would like to leave my #8 in place with a 60a cb and add a #10 with a 25a CB. Those would be running at 40a and 20a respectively.

It looks like I have found two circuits that I can remove from the main breaker box that can be use to add another 25a 2 pole circuit. I believe I could remove the two jumpers and connect the 25a line up to the smaller set of fuses. That would mean no breaker panel.

No,, the #8s are too small. Read the 125% requirement.

 

[600SL]

Couldn’t those two smaller red and black jumper wires be removed as a temporary fix? The house may not be as warm as desired, but the circuit won’t be running right at breaker capacity anymore.

Ive been thinking about that but I am not sure if I have this figured out yet.

 

[mm08822]

Try pulling the small fuses out. That will drop the heater to 10kw. See if it is able to maintain temperature.

If 10kw is adequate you could stay with a single 60A circuit.

Right, but he's fed the AH with #8 NMB. Long term, it needs to be increased to #6 and the additional circuit.

 

[600SL]

Try pulling the small fuses out. That will drop the heater to 10kw. See if it is able to maintain temperature.

If 10kw is adequate you could stay with a single 60A circuit. Simple, done.

No idea if yours is but many furnaces/heat kits are substantially oversized.

That works great. It's actually relatively warm out now but I boosted the heat setting to get the E-heat to run and it maxed out at 42a. Definitely a safer way to run for the next couple of days until I can get a proper CB.

 

[600SL]

No,, the #8s are too small. Read the 125% requirement.

Isn't that 125% over the running current which once I correct everything will be 40a.

 

[reader2580]

I hope proper breaker means a second smaller breaker for a second circuit.

 

[600SL]

I hope proper breaker means a second smaller breaker for a second circuit.

Yes they will be a 60a and a 25a.

 

[mm08822]

Isn't that 125% over the running current which once I correct everything will be 40a.

125% of 40A is 50A. #8 Copper NMB is only rated for 40A, so you need to go to #6 Copper NMB. You could use a 60A cb.


ETA: The minimum ampacity numbers all seem to include 9A above the 125% heater value. It is for the blower that is tied into L1/L2.

Technically(!), it would need to be #4 Copper if NMB b/c the MCA value exceeds 55A. THHN rating is 65A for #6 Copper.

 

[mm08822]

Yes they will be a 60a and a 25a.

And #6 Copper NMB and #10 Copper NMB.

 

[600SL]

125% of 40A is 50A. #8 Copper NMB is only rated for 40A, so you need to go to #6 Copper NMB. You could use a 60A cb.

Thanks.

I was thinking of my wire as THHN. that's what I get after wiring a shed in THHN. Its possible I have #6 NMB in place but I will need to double check.

 

[600SL]

My bad it is 6-2.

 

[Bert_]

If it keeps up with 10kw I would leave the second circuit disconnected permanently.

 

[dave*99]

Thanks.

I was thinking of my wire as THHN. that's what I get after wiring a shed in THHN. Its possible I have #6 NMB in place but I will need to double check.

THHN would need to be in conduit.

 

[mm08822]

The 6-2 NMB is in the shed or to the AH?

 

[600SL]

If it keeps up with 10kw I would leave the second circuit disconnected permanently.

I imagine it will keep warm but it may loose efficiency below about 10°F at -2°F the compressor completely shuts off. Latest forecast are not showing any negative numbers on the horizon.

 

[600SL]

The 6-2 NMB is in the shed or to the AH?

shed? 6-2 NMB goes from the CB to a disconnect I have on the outside of the air handler. From the disconnect is probably separate cables form what the 6-2 was made of or some THHN I had from my garage.

 

[600SL]

THHN would need to be in conduit.

And it is in my garage.

 

[Bert_]

I imagine it will keep warm but it may loose efficiency below about 10°F at -2°F the compressor completely shuts off. Latest forecast are not showing any negative numbers on the horizon.

Efficiency? Resistive electric heat is 100% no matter how you slice it

 

[mike93lx]

Efficiency? Resistive electric heat is 100% no matter how you slice it

The heat pump loses efficiency and he needs the resistive backup

 

[wyliesdiesels]

I could be mistaken but I think that the chart (have to open it and rotate it) is saying that if a single breaker is used between 208V and 240V then one needs wire gauge and a breaker rated between 80 amps and 90 amps that can carry L1, L2, L3, L4. But if one uses two breakers, one breaker can be between 50 and 60 amps for L1, L2 and the other breaker for L3, L4 should be between 25 amps and 25 amps. I only see one pair of wires coming to the unit in the photos so it sounds like it needs to be wired between 80 and 90 amps since only one set of wires is carrying both loads L1, L2 and L3, L4. The alternative is to put in 2 breakers and run a smaller gauge wire.

fixed it for you. a double pole breaker is considered 1 breaker not 2.

 

[BurtEggley]

fixed it for you. a double pole breaker is considered 1 breaker not 2.

Ok, I'll buy that explanation.

This is what I see in the specs. Adding a second circuit of 25 amps seems easier than running an 80 - 90 amp service or outdoor subpanel, then another two circuits in that panel along with with their double pole breakers, then the disconnects. It could be done either way but I think he might already have the wires installed for the 60 amp circuit. He just can't run L3 and L4 off them too. They have a week of very cold weather back there right now from what I understand.


Or

 

[600SL]

Ok, I'll buy that explanation.

This is what I see in the specs. Adding a second circuit of 25 amps seems easier than running an 80 - 90 amp service or outdoor subpanel, then another two circuits in that panel along with with their double pole breakers, then the disconnects. It could be done either way but I think he might already have the wires installed for the 60 amp circuit. He just can't run L3 and L4 off them too. They have a week of very cold weather back there right now from what I understand.


Or

Yes the first one is what I'm looking to do, but I was planning for unfused disconnects.

 

[larry4406]

This has been an interesting read. Thank you all!

The heat pack unit is a Carrier KFCEH3001F15B. This is a 15KW 208/240 single phase fused unit. The installation manual is here https://literature.neuco.com/CRkfceH.pdf

It talks to the dual circuit feed method shown in Post 105's first picture. A single circuit feed is possible using a factory-authorized kit (which is not described and the OP acknowledged).



Below is Figure 8 which shows the dual circuit. Figure 12 is not relevant (24 and 30 KW 3-phase). Figure 13 is not relevant (24 and 30 KW single phase). Figure 14 is not relevant (24 and 30 KW single phase).


Table 3 provides the wiring information.

• Circuit 1 is L1/L2, 40 amps, 58.5 min ampacity, 6 AWG min with 10 AWG min ground
• Circuit 2 is L3/L4, 20 amps, 25.0 min ampacity, 10 AWG min with 10 AWG min ground

The residential heat pumps I have encountered in my carrier have always been on 3 separate breakers. A large 2-pole breaker for the heat pack (40-60A typical), a smaller 2-pole breaker for the air handler (20-30A typical), and a 2-pole breaker for the outdoor unit (30-60A typical).

At work, we mainly install gas furnaces but occasionally we install heat pumps. I have to remind the electrician to pull the additional circuit for the heat pack.

The Goodman heat pump in my house has 60A for the heat pack, 30A for the air handler, and 30A for the outdoor unit.

 

[mike93lx]

This has been an interesting read. Thank you all!

The heat pack unit is a Carrier KFCEH3001F15B. This is a 15KW 208/240 single phase fused unit. The installation manual is here https://literature.neuco.com/CRkfceH.pdf

It talks to the dual circuit feed method shown in Post 105's first picture. A single circuit feed is possible using a factory-authorized kit (which is not described and the OP acknowledged).



Below is Figure 8 which shows the dual circuit. Figure 12 is not relevant (24 and 30 KW 3-phase). Figure 13 is not relevant (24 and 30 KW single phase). Figure 14 is not relevant (24 and 30 KW single phase).


Table 3 provides the wiring information.

• Circuit 1 is L1/L2, 40 amps, 58.5 min ampacity, 6 AWG min with 10 AWG min ground
• Circuit 2 is L3/L4, 20 amps, 25.0 min ampacity, 10 AWG min with 10 AWG min ground

The residential heat pumps I have encountered in my carrier have always been on 3 separate breakers. A large 2-pole breaker for the heat pack (40-60A typical), a smaller 2-pole breaker for the air handler (20-30A typical), and a 2-pole breaker for the outdoor unit (30-60A typical).

At work, we mainly install gas furnaces but occasionally we install heat pumps. I have to remind the electrician to pull the additional circuit for the heat pack.

The Goodman heat pump in my house has 60A for the heat pack, 30A for the air handler, and 30A for the outdoor unit.

How big are the air handlers that they need a 30a circuit? 120 or 240V? Do they contain smaller heat strips in addition to the blower?

My first floor unit (AH for a 3 to heat pump and 60k btu gas furnace) is running right now and drawing 236 watts

 

[larry4406]

How big are the air handlers that they need a 30a circuit? 120 or 240V? Do they contain smaller heat strips in addition to the blower?

My first floor unit (AH for a 3 to heat pump and 60k btu gas furnace) is running right now and drawing 236 watts

All the heat pumps I have experience with are 240V. I don't know the size of the blower in the cabinet. The heat packs have always been an add-on device to the unit; usually the cover has a blank check box where the installer marks it up to denote the heat pack he installed if there is one.

 

[mike93lx]

All the heat pumps I have experience with are 240V. I don't know the size of the blower in the cabinet. The heat packs have always been an add-on device to the unit; usually the cover has a blank check box where the installer marks it up to denote the heat pack he installed if there is one.

My outdoor units are 240V but all three air handlers are on 15A 120V circuits.

 

[Bert_]

The heat pump loses efficiency and he needs the resistive backup

Yes, but I don't think are worrying about the heat pump right now. I believe the 600SL said he switched the thermostat to EM.

The electric coils either keep up or they don't. If 10kw keeps up, leave it disconnected. If it won't maintain temperature then run the second circuit.

 

[mike93lx]

Yes, but I don't think are worrying about the heat pump right now.

The electric coils either keep up or they don't. If 10kw keeps up, leave it disconnected. If it won't maintain temperature then run the second circuit.

I get that. His post was referring to the adequacy of only 10kw of heat, which is why the heat pump efficiency was brought up

 

[Bert_]

I get that. His post was referring to the adequacy of only 10kw of heat, which is why the heat pump efficiency was brought up

So just run it and find out?

Maybe I'm a little biased since I've seen so many oversized heat kits.

 

[mike93lx]

So just run it and find out?

Maybe I'm a little biased since I've seen so many oversized heat kits.

I'm not advocating any approach in those posts.

You seemed confused about the efficiency comment, which is what I was addressing.

 

[600SL]

This has been an interesting read. Thank you all!

The heat pack unit is a Carrier KFCEH3001F15B. This is a 15KW 208/240 single phase fused unit. The installation manual is here https://literature.neuco.com/CRkfceH.pdf

It talks to the dual circuit feed method shown in Post 105's first picture. A single circuit feed is possible using a factory-authorized kit (which is not described and the OP acknowledged).



Below is Figure 8 which shows the dual circuit. Figure 12 is not relevant (24 and 30 KW 3-phase). Figure 13 is not relevant (24 and 30 KW single phase). Figure 14 is not relevant (24 and 30 KW single phase).


Table 3 provides the wiring information.

• Circuit 1 is L1/L2, 40 amps, 58.5 min ampacity, 6 AWG min with 10 AWG min ground
• Circuit 2 is L3/L4, 20 amps, 25.0 min ampacity, 10 AWG min with 10 AWG min ground

The residential heat pumps I have encountered in my carrier have always been on 3 separate breakers. A large 2-pole breaker for the heat pack (40-60A typical), a smaller 2-pole breaker for the air handler (20-30A typical), and a 2-pole breaker for the outdoor unit (30-60A typical).

At work, we mainly install gas furnaces but occasionally we install heat pumps. I have to remind the electrician to pull the additional circuit for the heat pack.

The Goodman heat pump in my house has 60A for the heat pack, 30A for the air handler, and 30A for the outdoor unit.

This is the conclusion I came to and am ordering parts for after figuring out all of this. Thanks for posting it so well clarified.

 

[600SL]

Efficiency? Resistive electric heat is 100% no matter how you slice it

That is a good question. Seems all legit except if its true why have a heat pump to begin with. I honestly cant figure that out. Only answer I can come up with is that were being lied to and told by the energy companies that heat pump is more efficient than resistive heating, so that we wast more energy. Its all a conspiracy theory.

Answer from AI.

 

[mike93lx]

That is a good question. Seems all legit except if its true why have a heat pump to begin with. I honestly cant figure that out. Only answer I can come up with is that were being lied to and told by the energy companies that heat pump is more efficient than resistive heating, so that we wast more energy. Its all a conspiracy theory.

A heat pump is not resistive heat and is far more efficient, assuming there is enough heat in the air to run

 

[600SL]

A heat pump is not resistive heat and is far more efficient, assuming there is enough heat in the air to run

see my Ai update

 

[mike93lx]

see my Ai update

I don't need an Ai screenshot to know how a heat pump works.

 

[mm08822]

This is the conclusion I came to and am ordering parts for after figuring out all of this. Thanks for posting it so well clarified.

Just remember that Larry's example is for similar but different equipment. You need to use your own specs.
Your equipment includes the blower load on L1/L2. Others may have it as another seperate circuit.