Wiring for Garage Heater

[Matt Wilson]

Hi folks,

I want to buy a heater for my garage (shop). The biggest one I can find for a price I can afford is advertised to put out 19,000 BTU's. It is a 240V unit that has a NEMA 6-30P plug. I have an outlet I installed in my garage to accomodate a 240V 50A welder. The outlet (receptacle) is a NEMA 6-50R.

Is it safe for me to make an adapter to go between the 6-30P plug of the heater and the 6-50R receptacle? From the standpoint of current draw, I know the 50A circuit will be safe. It is obviously rated for much higher capacity than what the heater will require. However, I know very little about the different 240V circuit types, so I don't know if there may be incompatibilities that may exist in other ways (ground vs. neutral, 2 hots vs.?, etc).

Any suggestions or advice are appreciated.

Also, I'd like to bounce the idea of this heater off you guys. Putting out 19K BTU's, do you expect that will be satisfactory to keep the garage reasonably warm in winter? My garage is about 24' x 24', 9 feet tall, with 2 of the 4 walls insulated, and garage door is insulated as best as it can be, ceiling is not insulated (not yet, maybe someday). Concrete floor. Comfortable temp for me would be 60 - 70 degrees. Outside temps here do not often go below 20 degrees. Do you think this heater will be adequate?


Many thanks.....

 

[Todd.Brock]

The one thing folks may suggest is downsizing the breaker to a 30amp. The heater will self destruct before it trips the breaker, if ever on a 50 amp circuit. I would use a receptacle that matches the requirements of the heater.
I an in process of installing a dayton g73 (Fahrenheat version) and it is 5000 watts and I think 17 k btu. It's rated for a 400 to 500 sq.ft. per the box. It requires a 30 amp circuit

 

[royalton10]

I have the Dayton G73 heater mentioned above in a 24x24 with 8' ceilings. I am in central Ohio. Ceiling has 12" of insulation.

This heater will run me out and can add 10-15 degrees in less than 2 hours if temps are below 20 degrees.

Bear in mind that other heaters are copying the G73 name and are not the Dayton brand.

I added a line thermostat on the wall to control the temperatures. I also added a 240v pole switch as the kill switch, it is beside the thermostat.

 

[royalton10]

Here are some pictures of my Dayton G73 heater installation:

Hope this helps.

Doug

 

[Todd.Brock]

Doug is correct. I said G73 b/c more folks recognize this name. The Fahrenheat version is the same heater. They are made by Marley. Specss, directions, etc. See some other threads and you will see this. Beware of Newair G73. That is NOT the same heater as Dayton,which Apparently is Grainger's house brand or the Fahrenheat version.

my point was that based on the recommendations of the manufacturer you may need to be sure the heater is sized correctly

 

[awdblazer]

yah you will be safe to do that (well here in canada you could)
all the breaker does is protect the wire, so i would assume it is wired with #6 which is good for 65 amps

 

[Thruxton]

yah you will be safe to do that (well here in canada you could)
all the breaker does is protect the wire, so i would assume it is wired with #6 which is good for 65 amps

I don't think so. Read Todd.Brock's comment above. And if you look at the Dayton or Fahrenheat installation sheets you will see that different breaker ratings are spec'ed depending on the heat output (i.e. current draw) they are wired for. Overcurrent protection involves more than just making sure wires don't melt!

 

[Matt Wilson]

Nice-looking setup there, Doug.

Good comments from everyone regarding the over-current protection. I was only looking at it from one angle, which was that the 50-Amp circuit would be capable of handling the requirements of the heater. But it sounds like it is also perfectly capable of letting the heater burn itself up, along with anything else that might be nearby, in the event of a heater malfunction.

I suppose I could tie into the existing 50-Amp line for the welder, and hook up a 30-Amp outlet right next to the 50-Amp outlet. I wonder there is such a thing as a 6-30R receptacle that includes an internal breaker. I took a brief look just now on the Lowes website, but was unable to find anything. I didn't look very long, though, as I am on my lunch break. I will stop by Lowes, Home Depot or other place to see what they have. Let me know if you think this seems feasible/safe.

Also, let me know if there is any other reason that the heater's 6-30P circuitry would be incompatible with the existing 50-Amp wiring that I ran for the welder, so long as I use a 30-Amp outlet and breaker. In other words, I want to be sure there is no issue with wires in the two circuits being intended for different purposes (i.e., ground vs. neutral, 2 hot wires vs. not, etc.). Like I say, I am not a wiring guy, but I can do basic things, and I want to be sure I'm being safe about it all.

Another option I just thought of is tying into the circuit for the dryer. When I get home, I'll try to remember to look at what kind of outlet it has, and see if it would appear to be compatible. I welcome information on this, too.

Thanks again.....

 

[VHF]

Wouldn't plugging a 5500W heater that draws 23A into a 50A circuit be OK unless the manufacturer specifies it must be on a circuit with a 30A breaker? The breaker is to protect the building wiring, not the appliance!

6-50R and 6-30R both use two hots and a ground, so no problem with compatibiltiy if you make an adaptor.

Dryer circuits are 30A. Modern (1996+) dryer recepticals have 4 wires (hot, hot, neutral, ground). Presumably the heater doesn't utilize a neutral, so you could make an adaptor from a dryer plug that connected hot, hot, and ground to a 6-30R receptical.

 

[Matt Wilson]

Thanks, VHF! My dryer outlet is actually only a 3-prong outlet, looks like a NEMA 10-30 (3-pole, 3-wire).

I wonder if this would be compatible/safe, assuming I make with the appropriate adapter.