View Full Version : 240 volt Garage Heater ?


Pug}{maN
12-29-2011, 09:11 AM
i see lots of 240 volt Garage Heaters when im looking for a 220 to plug in to ware my compressor is , is the 240 the same ? or will it work ? and i see the plug is not like my 220 eather...

the one im looking at...

http://www.homedepot.com/h_d1/N-5yc1v/R-202909806/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

bad5x8
12-29-2011, 09:31 AM
I have a similar heater in my garage. I only have one 240volt line in my garage, so to run the heater, I unplug my air compressor. I have "welder" plugs on both pieces of equipment so they both plug into the same outlet which is the "50 amp" welder outlet.
That plug looks like the 30 amp plug.

Charles (in GA)
12-29-2011, 10:17 AM
The actual voltage should be near 240v. Anything you see that says 220 or 230 or 240 will work. I suppose the "nominal" voltage is 230, however, virtually everywhere in the country, the voltage supplied to you is 240 and sometimes slightly more (242 or so). 220v hasn't been actively supplied to users in many years and to call it 220 is, to electricians, a sign of inexperience, ignorance, lack of knowledge, whatever you want to call it (I'm not an electrician but I know better than to call it 220v.

Same goes for 120v. 115 is nominal, 110v is obsolete.

Not criticizing, just informing.

As far as plugs, there are plugs designed for 120v for 15 amp (the common appliance and device plug) and plugs designed for 20 amp (rarely seen on equipment but the receptacles are found in virtually every commercial establishment)

http://www.stayonline.com/reference-nema-straight-blade.aspx

http://www.americord.com/nema-charts

Plugs and receptacles are generally identified by their NEMA identification (National Electrical Manufacturers Association?)

Common household receptacle (NEMA 5-15R)
http://www.westernextralite.com/images/515r2.jpeg
and its mating plug (NEMA 5-15P)
http://www.westernextralite.com/images/515p2.jpeg

Commonly found in commercial use, 20a receptacle which accepts common household 15 amp plugs. (NEMA 5-20R)
http://www.westernextralite.com/images/520r.jpeg
Not so common 20a plug to mate with the above receptacle. (NEMA 5-20P)
http://www.westernextralite.com/images/520p.jpeg

For 240v we will dispense with the 15 amp versions.... here is the 20 amp receptacle (NEMA 6-20R)
http://www.westernextralite.com/images/620r.jpeg
and here is the mating plug that is common on air conditioners and small air compressors (NEMA 6-20P)
http://www.westernextralite.com/images/620p.jpeg

here is the 30 amp 240v receptacle used on heavier air compressors, heaters, etc. (NEMA 6-30R)
http://www.westernextralite.com/images/630r.jpeg
And here is the plug for the cord for 30 amp 240v (NEMA 6-30P)
http://www.westernextralite.com/images/630p.jpeg

Charles

ert01
12-29-2011, 10:35 AM
It will work.

A heater is basically just a big resistor with a fan on it.

Voltage = Amperage x Resistance

Resistance is a fixed value. It doesn't change unless the heater has a hi/lo setting. Even if it does, the resistance is a fixed value for each coil, the setting switch would just add or remove coils from the circuit basically.

Voltage and amperage can change though. If the voltage goes up, amperage goes down. If the voltage goes down, then the amps go up.

That heater in particular is 5600W.

Watts(power) = Volts x Amps

Let's put in some values and see what happens...

You hook it up to 208V:
5600 = 208 x A
A = 26.92A

Now of you hook it up to 220V:
5600 = 220 x A
A = 25.45A

And at 240V:
5600 = 240 x A
A = 23.33A

As you see, the current being drawn will change depending on the voltage being applied. You could technically hook this up to 120V even but it would draw a silly amount of current (46.66A) and the fan might not run.

Most electrical appliances rated in the 208-240V range will work on a variety of voltages but the actual current being drawn might be slightly different then the nameplate rating.

Pug}{maN
12-29-2011, 11:15 AM
wow , thanks guys , lots of info there ! ill just put a plug like mine (NEMA 6-20P) on the thing and be good !

curiousB
12-29-2011, 11:16 AM
This is incorrect the wattage rating is different based on the voltage supplied. If the device is rated at 5600W at 240 VAC then the resistance of the heater is

W=V * I
I = V/R
therefore:
W=V^2/R

From 5600 @ 240VAC you get 23.333 A of current and 10.28571 Ohms of resistance

Therefore you can now solve for all cases:

240VAC 5600W
220VAC 4705W
208VAC 4206W
120VAC 1400W


So more heat the more voltage. In fact wattage rises with the square of voltage hence the huge benefit of 240 over 120VAC (four times more heat for doubling of the voltage).

Charles (in GA)
12-29-2011, 04:17 PM
wow , thanks guys , lots of info there ! ill just put a plug like mine (NEMA 6-20P) on the thing and be good !

You need to use a NEMA 6-30P and its mating receptacle, in addition, you need to use 10 gauge wire and a 30 amp breaker.

You CANNOT use a 20 amp plug (NEMA 6-20P) on a device that draws more than 20 amps.

Heaters are considered continuous load and as such must be on a circuit whose rating is at least 125% of the heaters rating

23.33 amp times 125% equals 29.16 amps minimum circuit rating needed for the heater.

Charles

Pug}{maN
12-29-2011, 04:53 PM
my breaker is 2 small ones all they say is 120/240 on them made buy t&b , the wire is orange in color thats all i know...other than the outlet looks to be the NEMA 6-20R..

Gregishome
12-29-2011, 06:28 PM
my breaker is 2 small ones all they say is 120/240 on them made buy t&b , the wire is orange in color thats all i know...other than the outlet looks to be the NEMA 6-20R..

As Charles posted above, and also like the Home Depot specifications state on the link you posted above, the heater will require a nema 6-30r receptacle / 30 amp circuit.

Charles (in GA)
12-29-2011, 06:55 PM
my breaker is 2 small ones all they say is 120/240 on them made buy t&b , the wire is orange in color thats all i know...other than the outlet looks to be the NEMA 6-20R..

OOPS, by "small ones" do you mean two very narrow ones sandwiched into one wider breaker position? and with two handles, that are NOT connected together?

If so, thats a tandem breaker..... two single pole breakers that occupy the space of one "normal" breaker. Regular breakers, (except for Square D QO series) are one inch wide, and the half width breakers are.... half inch wide.

(Square D, which this is NOT, uses standard breakers that are 3/4" wide and the half width breakers are actually two breakers made into one 3/4" wide body with two handles)

Anyhow, if you do have the two tandem breakers (I didn't realize that Thomas & Betts made half width breakers, and T&B is no longer in the circuit breaker and panelboard manufacturing business) then what you have are two separate 120v breakers that are on the same stab.

Pics would help greatly.

Charles

jmauld
12-29-2011, 07:11 PM
i see lots of 240 volt Garage Heaters when im looking for a 220 to plug in to ware my compressor is , is the 240 the same ? or will it work ? and i see the plug is not like my 220 eather...

the one im looking at...

http://www.homedepot.com/h_d1/N-5yc1v/R-202909806/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

That looks similar to this one:
http://www.northerntool.com/shop/tools/product_200395481_200395481

Which I just got for christmas. I'm considering taking it back and trading it in for a heater that's made in the USA like this one appears to be:
http://www.northerntool.com/shop/tools/product_595_595

The fahrenheat model can also be hung from the ceiling which is a big plus for me.

Pug}{maN
12-29-2011, 08:18 PM
these to are the ones that make up my 240 for my Compressor.....

http://img.photobucket.com/albums/v324/pughman/Katiespics006-1.jpg

Gregishome
12-29-2011, 08:30 PM
Those are classified as single pole breakers and to be code approved for a 240 volt load, should have a mechanical tie strap on them so they will trip at the same time.

on edit: It appears you have 12 ga. 20 amp wiring to your compressor. Not a suitable 30 amp rating for the heater you are wanting to purchase. The wire to the heater has to be a 10 gauge to be approved, with a two pole 30 amp breaker.

Pug}{maN
12-29-2011, 09:32 PM
here is a pic of the wire...

http://img.photobucket.com/albums/v324/pughman/ChrissStuff004.jpg

curiousB
12-29-2011, 10:23 PM
Not to mention one looks to be a 30A breaker and the other a 20A breaker..... you can't feed a branch circuit with different sized breakers on each phase.

So to be compliant you need:

- 10-2 wire from panel to the heater.
- a two pole 30A breaker for the panel or two single pole 30A breakers with a tie bar to lock the trip levers to each other.
- Another 240 V circuit for your compressor. You will trip the heater breaker if compressor is sharing same branch circuit as heater. You might be able to get away with 20A dual pole breaker and 12-2 wire for the compressor branch circuit.

Justanoldguy
12-30-2011, 12:41 AM
Wow. Mind boggling.
Everything here is 240 volt and nothing here looks anything like what you guys have in the USA. Even the plugs, switches ets are totally different. I think I will stay in NZ.

brucer
12-30-2011, 09:10 PM
post a pic of the receptacle, it should be a 20amp receptacle....

to plug into the 20amp receptacle you'll probably have to go with a 4000watt heater thats rated for the 20amp circuit.. several of the milkhouse style heaters will work, and also lowes sells one online made by King for like $150 I think..

and you need to get the correct breaker and toss the 2 single breakers you have in there now in your toolbox..

pattenp
12-30-2011, 09:32 PM
To OP:
The yellow jacket romex is #12 good for 20A and the orange jacket romex is #10 and good for 30A. If your compressor is on the orange cable you can upgrade the breaker to a 30A 2 pole and replace the outlet with a 6-30R. You will need to covert the wire and plug on your compressor to match the 30 amp capacity of the new outlet.

On a side note you should put a bushing on the end of that PVC conduit to prevent chaffing of the two romex cables.