Garage Heater Wiring Help

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Old 01-22-21, 06:21 PM
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Garage Heater Wiring Help

This may be a long post, but thanks for any help you guys can offer! I am installing a 240V garage heater that will be hardwired. I already have 220V wiring/circuit on the same wall that was for an old hot tub no longer here but need to extend the wiring up higher on the wall to be able to reach the heater. Here are my questions..

#1. The heater is 5000W with a max amp of 20.9 (21). Does that mean it should be on a 30amp breaker?

#2. Wiring should be 10 gauge correct?
#3. - How do I know if I need 10/2 or 10/3? I attached a wiring diagram from the instructions if that helps.



4. Most confusing part for me (photo attached).. The current breakers in my box listed for the hot tub are spots #25 AND #27 ("Hot tub" is written across both spots on the panel door). One is a 20A and one is a 15A. Do I pull both breakers out and replace with a 2 pole 30 amp breaker filing in those same two spots?



Thanks for any help!
 
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Old 01-22-21, 06:29 PM
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1) yes..... the heater should be on a 30A 240v circuit.
2) yes.... wiring should be #10.
3) you have a straight 240v load. You need 10-2 w/ground.

Double check..... you may find the circuit on #27 and #29.
It would typically be wiring from a cable with red and black (or white and black) in the same jacket.
 
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Old 01-22-21, 06:44 PM
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You are going to need to verify which breakers serve the old wiring. The breaker should have been a 2 pole breaker or handle tied.
 
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Old 01-22-21, 06:54 PM
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How would I go about verifying which breakers control the wiring I have out in my garage wall? Breaker #29 is not labeled on the panel door... Here is a better shot of how it's wired..
 
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Old 01-22-21, 06:57 PM
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There is a black wire on #27........... there is a red wire on #29.
Do they go into the same cable ???

Those are only 15A and 20A breakers. If one of them supplied a spa..... it must have been a portable one and it would have been a 120v model.
 
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Old 01-22-21, 07:14 PM
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The hot tub was a full sized hot tub outdoors.

Ok so upon further investigation the red and black wires on the very bottom two breakers run from the breakers to a surge protector unit box inside the panel. Then from the surge protector unit there is a green/yellow striped wire and a solid white wire that leaves the surge protector and runs up to long block of screws where a bunch of wires are screwed in. None of the wires are in their own casings inside the panel so it's hard to tell what is what. Here are some photos..



 
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Old 01-22-21, 07:20 PM
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Looks like the hot tub was disconnected and a surge protector connected in its place.

If you had a full size hot tub.... it would have been connected to a 2P40A or 2P50A circuit breaker with large wire. Look in your panel for a large red and black wire that is not connected.

I see some larger wires in the bottom left corner taped off.
 
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Old 01-22-21, 07:26 PM
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Bingo! Found them. Three heavy gauge wires taped off. These have to be the hot tub I would assume. So can I just put a 2 pole 30 amp breaker in the empty spot pictured (will it accept that?) And then run these two wires into the new breaker?


 
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Old 01-22-21, 07:45 PM
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That is at least 10-3 cable with ground. Red, black, white and bare ground.
The ground should be connected to the ground block.
Cap off the white wire at both ends.
The red and black will go on a 2P30A breaker.
 
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Old 01-22-21, 07:50 PM
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Thank you, you have been a heck of a help! I also see that I have a Cutler hammer "Tan" handled breaker panel which requires a specific type of breaker "CH" style with tan handle not black. Luckily looks like Home Depot stocks them.
 
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Old 01-22-21, 08:07 PM
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One more question, you stated to cap the white wire and use the red and black only... however on the heater wiring diagram it states to use the bare ground, black and white wires? Do I just ignore that and use the red and black anyway? I assume swap the white wire for the red at the heater terminal L1 in diagram?
 
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Old 01-22-21, 08:09 PM
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Looking at your panel picture.... the bus bar connections look like crap.
They are supposed to be clean and shiny. Those look dark and corroded.

I wouldn't recommend a DIY cleaning but technically they should be cleaned.
That can only be done with the main breaker shut off.
They should be cleaned and a small bit of anti oxidant used to preserve them.


Yes...... use red and black - cap off white.
 
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Old 01-22-21, 08:20 PM
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Thanks - I plan on turning the entire panel off from the main breaker when I install the new breaker and do the wiring etc... so I will clean the contacts with a small wire brush while I'm I'm there. I'll report back if I have any issues. Will be doing all this tomorrow afternoon. Thank you again!
 
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Old 01-23-21, 06:20 AM
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The instructions figured that a xx-2 cable would have been run since only 2 conductors and a ground are needed. You have 2 identified hots so use them.
 
 

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