Mr Cool DIY 36k wiring

[APG12]

I am planning a Mr Cool DIY 36k install and purchasing all of the supplies in advance. I have a few questions on wiring if anyone can help.

These are the specifications: Minimum Circuit Amp 25, Max Fuse 35 Amp

On the Ingrams site, they state that 8/3 wiring is required and an 8ga whip, but I've seen recommendations here for 10/2. Is 10awg sufficient? And why are they recommending a 3 wire? I will likely use THHN through conduit.


Also, is a non-fusible disconnect sufficient? 35amp breaker?


My buddy will be doing the majority of the wiring, since he is much more electrically inclined than I am, but I want to have everything in hand ahead of time.

Thanks in advance for any help!

 

[MattT]

Best thing would be to download the installation manual and see what it says because the website may be wrong.

If it calls for fuses then use a fused disconnect. If it calls for overcurrent protection you can use a breaker. You can use HVAC sizing for the wiring unless the manual states otherwise. And it'll tell you how many conductors you need. It's probably L1, L2 and ground but check it doesn't require a neutral.

 

[APG12]

Best thing would be to download the installation manual and see what it says because the website may be wrong.

If it calls for fuses then use a fused disconnect. If it calls for overcurrent protection you can use a breaker. You can use HVAC sizing for the wiring unless the manual states otherwise. And it'll tell you how many conductors you need. It's probably L1, L2 and ground but check it doesn't require a neutral.

Thanks for the response. I’ve checked the manual but it wasn’t much help.

 

[MattT]

I’ve checked the manual but it wasn’t much help.

More like USELESS!!!! Sorry I didn't realise the documentation would be that bad.

Personally I'd run 3/4" conduit to a 60A fused disconnect then wait until you get the unit in and check the nameplate before doing/buying anything else.

 

[Git]

Similar discussion on an electrical forum you may find interesting:

This is from one of their moderators:

I'd use the 35A breaker with 10ga wire, especially if it's not a super short run or there may be ambient temps over 40*C.

http://forums.mikeholt.com/showthread.php?t=177763

 

[APG12]

Thanks for the info guys. I’d much rather use 10awg than 8 if I can.

 

[PoorOwner]

I am no electrician but my understanding from what you posted.
you need to supply at a minimum 25A wiring, but the overcurrent protection (fuse) CANNOT be bigger than 35A.

10 AWG meets requirement of 25A wiring and you can put in fuse of 30A and everything meets the requirement.

always check the number on the nameplate of the actual unit.

 

[APG12]

https://www.garagejournal.com/forum/showthread.php?t=340321

This thread has some pretty good information that's in line with my findings. Any electricians reading this that can confirm?

 

[eddieK]

I am planning a Mr Cool DIY 36k install and purchasing all of the supplies in advance. I have a few questions on wiring if anyone can help.

These are the specifications: Minimum Circuit Amp 25, Max Fuse 35 Amp

On the Ingrams site, they state that 8/3 wiring is required and an 8ga whip, but I've seen recommendations here for 10/2. Is 10awg sufficient? And why are they recommending a 3 wire? I will likely use THHN through conduit.


Also, is a non-fusible disconnect sufficient? 35amp breaker?


My buddy will be doing the majority of the wiring, since he is much more electrically inclined than I am, but I want to have everything in hand ahead of time.

Thanks in advance for any help!

30 amp circuit - with #`10THNN or romex - Use 25 amp fuses at disconnect. 2 wires AND a ground.

 

[eddieK]

Best thing would be to download the installation manual and see what it says because the website may be wrong.

If it calls for fuses then use a fused disconnect. If it calls for overcurrent protection you can use a breaker. You can use HVAC sizing for the wiring unless the manual states otherwise. And it'll tell you how many conductors you need. It's probably L1, L2 and ground but check it doesn't require a neutral.

Whe the panel is not within 50 feet and in clear sight, you must provide a disconnect, fused or not.

This is so no one can turn on the power if you are working on it.

 

[APG12]

30 amp circuit - with #`10THNN or romex - Use 25 amp fuses at disconnect. 2 wires AND a ground.

Thanks for the help. Why the fused disconnect as opposed to non fused? I understand the difference between the two, but what calls for one over the other? Just trying to learn a little.

 

[Bondersma]

Hi APG12

Just installed my Mr Cool 36k in my 30x40 barn today. I used 10-2 AWG wire ( 2 wires, ground ) approx. 50' run and a 10 AWG whip with a non fused disconnect. Running a 30 amp breaker. I went this route after many recommendations , but every setup is different and be sure you are positive in what you are doing.

I wish I would have done it sooner, its absolutely awesome and couldn't be happier with how it turned out. Works really really well. I was actually cold after a while of it running. I made a nice little cement pad for it to sit on with some landscape blocks mounted to the pad to raise it up approx 4" , then made a drain going through the pad for the condensation line . A lot of water will exit this line be sure for proper flow of it and a good place to have the run off go.

Bob

 

[APG12]

Hi APG12

Just installed my Mr Cool 36k in my 30x40 barn today. I used 10-2 AWG wire ( 2 wires, ground ) approx. 50' run and a 10 AWG whip with a non fused disconnect. Running a 30 amp breaker. I went this route after many recommendations , but every setup is different and be sure you are positive in what you are doing.

I wish I would have done it sooner, its absolutely awesome and couldn't be happier with how it turned out. Works really really well. I was actually cold after a while of it running. I made a nice little cement pad for it to sit on with some landscape blocks mounted to the pad to raise it up approx 4" , then made a drain going through the pad for the condensation line . A lot of water will exit this line be sure for proper flow of it and a good place to have the run off go.

Bob

Awesome. I’m looking forward to it.

 

[ant.foste]

I am planning a Mr Cool DIY 36k install and purchasing all of the supplies in advance. I have a few questions on wiring if anyone can help.

These are the specifications: Minimum Circuit Amp 25, Max Fuse 35 Amp

10 gauge wire, 35 amp fuses. Enjoy the cold when completed.

NEC 430 for anyone who says you can't put 30 wire behind a 35 amp protection device.

 

[Norcal]

10 gauge wire, 35 amp fuses. Enjoy the cold when completed.

NEC 430 for anyone who says you can't put 30 wire behind a 35 amp protection device.

If 12 AWG THWN was used it would be fine also, in this application 12 AWG THWN is 25A wire, with HVAC you wire to the minimum, & use the maximum fuse or circuit breaker allowed by the nameplate.

 

[ant.foste]

If 12 AWG THWN was used it would be fine also, in this application 12 AWG THWN is 25A wire, with HVAC you wire to the minimum, & use the maximum fuse or circuit breaker allowed by the nameplate.

Indeed, you are correct on the 12g wire.

 

[ncboat]

Just ran wire for my 36k and passed rough in. Like above 30 amp breaker, 10/2 with Siemens disconnect box with sevice receptacle and 25 amp fuse.

 

[rverheeck]

Hi APG12

Just installed my Mr Cool 36k in my 30x40 barn today. I used 10-2 AWG wire ( 2 wires, ground ) approx. 50' run and a 10 AWG whip with a non fused disconnect. Running a 30 amp breaker. I went this route after many recommendations , but every setup is different and be sure you are positive in what you are doing.

I wish I would have done it sooner, its absolutely awesome and couldn't be happier with how it turned out. Works really really well. I was actually cold after a while of it running. I made a nice little cement pad for it to sit on with some landscape blocks mounted to the pad to raise it up approx 4" , then made a drain going through the pad for the condensation line . A lot of water will exit this line be sure for proper flow of it and a good place to have the run off go.

Bob

Thanks Bob, I'm building the same exact size metal garage and I was wondering about the 36k and maybe four units in different areas of the building. Thank you again