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jbclbc 01-10-2006 01:35 PM

240v / 20.9A Heater
I will be installing a Dayton Electric Utility Heater #3UG73D in my garage.
It requires 240v. The power block on it has connections for White/Black/Green.
I have plenty of panel space. I have a 240v 30A breaker and 10-3 cable.
I've wired a 120/240v dryer outlet before (black(hot)/red(hot)/white(neutral)/green(ground)), but not 240v1p...


jbfan 01-10-2006 02:10 PM

Remark the white wire on both ends with a red or black magic marker. Connect the white and black wires onto the 2 pole breaker, and connect the ground wire to the ground bus.
Are you sure the termnial block shows for a white/black/green connection?

jbclbc 01-10-2006 02:18 PM

Page 3, Figure 7 shows:

"Black, White, Green (or bare Copper)" connecting to the power terminal block.

Page 5, Figure 9 shows:

"240V or 208V Phase 1" connecting to L1 & L2 (plus Ground).

Speedy Petey 01-10-2006 05:21 PM

I read both posts over twice. Is there a question?

I'm not sure what you are asking.
240v is simply two hots and a ground. Ground can be green or bare.
If you want to use the 10/3, use the black, red and ground. If you use 10/2 you can use the black and white and ground. The white must be re-marked black or red with a marker as JB said.

mekanic 03-18-2006 08:52 AM

wiring a 240V outlet (Canada)
I have had my 240V table saw wired (via shut-off) to an Hubbell Twist lock 3 prong outlet and with a matching cord and plug. Upon looking at the receptacle wiring I had the red and black wires connected to the receptacle and the bare wire to the green screw connection, The white wire is just sitting unused in the outlet box and at the service panel where the breaker is located. Shouldn't the White be connected to the neutral bar in the service panel and if so where does it connect at the receptacle when there is no connection screw for it? Thanks for your advice.

Speedy Petey 03-18-2006 10:20 AM

You do NOT need the white. More accurately you do not need the red.
You can run a two-wire, with ground, for a straight 240v circuit. The white can serve as a hot, it should be re-marked as black or red with a permenent marker though.

This is about the #1 comon misconception in electric. I mean that you MUST use red and black for 240v. This is not at all true.
Like I said, there is no connection for the white (as a neutral) because there is NO neutral in a 240v circuit.

timg 01-18-2007 09:46 AM

Sorry to dredge up an old post. But I plan to do a similar thing. I have an old fuse-based panel and plan on wiring up 240V from each side of the buses.

If I use 3 wire cable ("black or red"/white/bare) I just need to wire "black or red" to the hot on one bus, white to hot on the other bus (marked with "red or black" marker at each end) and the bare ground to the neutral block OR the panel 'chassis'? Which one?

Also, for a 4800W heater (20 to 22 amps depending on whether it is 240V or 220V), and a very short run (2-3 feet) I should use #12 wire with 30A fuses on each circuit?

Thanks for any help.


Speedy Petey 01-18-2007 03:18 PM

You can run a typical "2-wire" cable. 10/2 to be specific.
Yes, re-mark the white to a hot color such as black, red or blue.
You need #10 for this heater, on a two-pole 30 amp breaker.

timg 01-18-2007 04:32 PM

It is a fuse panel, not a breaker panel.

I can still run 240V by connecting the two hot wires to two seperate buses (please correct me if I'm using the wrong terminology) each with a 30A fuse.



Stubbie 01-18-2007 09:18 PM it look like this....

timg 01-19-2007 06:15 AM

Does my heater look like that? No it'll look like this:

Info on this website:

This isn't the exact one, but basically the same thing.

Here is a picture of my panel:

I had planned to install a hot wire on each side of the lower row with 30A fuses in each.

I was also wondering if I should wire the ground (green or bare) to the neutral bar or the chassis of the panel (like all the other bare wires for the 120V circuits).

Thanks so much.


jwhite 01-19-2007 06:47 AM

Put your ground with the other grounds.

You could use the double fuse pullout on the bottom for your new circuit.

And I would fill the unused fuse holes with something. even an old burnt out fuse.

timg 01-19-2007 08:08 AM

Thanks for the reply (and good advice on the open fuse holes.. common sense and I should have thought of that!)

By "with the other grounds" you mean to the chassis of the panel right? (The white wires are all neutral wires right?)

I don't understand what you mean by the double fuse pullout. Please explain how I could use this for my circuit.

Thanks so much, I'm learning a little by little.


jwhite 01-19-2007 08:29 AM

An electrician would say "can" or "enclosure", but "chassis" works in today's world, where computers and TV's and such use chassis grounds. :)

It looks, from here, like there is a fuse pullout at the bottom of your panel. Grab the handle and pull and you will have a fuse holder in your hands. If I am correct, then this meets the requirement for simultaneous disconnect of all hot conductors for a circuit.

Take that to an electrical supply house and they will sell you the correct fuses and fuse reducers if needed.

jwhite 01-19-2007 08:31 AM

On an added note. If you do not have enough ground screws left you can run one ground wire to a screw then pigtail several gounds together with a wire nut. The tail going to the screw must be the same size or larger than any of the others in your wirenut.

EG: pig tail one #10 and one #12 with a #10 tail to the can.

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