will 208V heater run on 240V

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Old 09-25-08, 04:38 PM
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will 208V heater run on 240V

Hello,

There is a nice heater on craigs list that says it is 208V single or 3 phase, 36A. Will this run on my single phase 240V supply to my garage (I have up to 50A breaker), or do I need a step-down transformer?

Thanks
 
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Old 09-25-08, 04:47 PM
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It may work on 240 volt single phase but the imporat part is see the nameplate to verify it and that heater do have two diffrent connection.

And keep in your mind the current drawage will be somehow higher than 208 volt circuit so that why I mention to see the nameplate to show the voltage rating and if it say 208-240 volts then you are fine but watch the wattage rating on that.

To hook up that type of unit heater if you look at the junction box on the heater itself it will useally show the wiring diagram for hooking up both 1 and 3.

All I am instering to see what the KW rating it may affect your connection.

Merci,Marc
 
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Old 09-25-08, 05:10 PM
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Thanks for the response. Here is some more info on the unit. I can pick it up new for about half price and would like to know if it can run in my garage as is or do i need a transformer? The heater is a Dayton model 2YU68, 7.5kW. This is what is has in the online info:

"Automatic reset linear thermal protector provides protection over entire length of element area to disconnect heater if normal operating temperatures are exceeded. Heavy-duty, totally enclosed motors. Aluminum-finned, copper-clad steel sheath heating element. 24V low voltage control circuit standard on all models except 3 and 5 kW single-phase units, which are wired for direct line voltage control. 3-phase models are phase balanced. 3-phase 30 and 50 kW units are wired for single- or two-stage low voltage control and contain two-speed motor for Hi/Low fan selection. UL and C-UL Listed (E154218). Meet NEC and OSHA requirements."

I think I read it comes wired as sigle phase.
 
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Old 09-25-08, 06:55 PM
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Ok I read the model number you provide .,

It can be wired for single or three phase.

It is a 7.5 KW heater.

The current drawage will be about 31.25 amp so you will need to run #8-2 W/G NM or #8 THHN/THWN in the conduit { red, black and green }

And you will need 40 amp breaker as well.

To hook up the heater for single phase you have to get all the heating elements run in parallel format like example here A-1 ,A-2 B-1,B-2 C-1,C-2

Here what you will do is get A-1 , B-1 , C-1 hook up to L1 while the A-2 , B-2 ,C-2 will be hook up to L2 { you will see the termail block IIRC } that how you hook up on single phase and that unit do work both 240 , 208 volts .

I think this heater do have interal thermosat otherwise a 24 volt thermosat will be used due the size of heater.

Merci,Marc
 
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Old 09-25-08, 07:08 PM
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Thanks, that is very helpul.
 
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Old 09-25-08, 07:13 PM
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That good I can able help you with the info.,, However I may did make a oversight but how big the subpanel you have in the garage and is this garage is attached or detached ?


Sorry about that part I somehow got my mind slipped for a min doing my paperwork and I say ohoh I miss something here.,,


Merci,Marc
 
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Old 09-25-08, 08:19 PM
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The 2YU68 appears to be made for 208V only; if you look at this catalog page you will see a different heater 2YU66 that is made for 240V, with an option to use it at 208V.

http://www.grainger.com/Grainger/wwg...e&CatPage=3890

-Jon
 
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Old 09-25-08, 08:44 PM
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Thanks Winnie for catching the blunder here I was not watching the number very close due the last digit got me { tsk tsk I should use the glasses }

However if you get this unit the other option which I do use it from time to time is Buck/Boost transformer to downstep the votlage from 240 down to about 208~210 volt depending on which one you use.

And basied with the heater size you listed.,, The B/B transfomer size will be 1.5 KW

{ if you run in B/B format it will handle pretty good amout of current due the secondary side will only adjust small step of voltage }

Merci,Marc
 
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Old 09-26-08, 05:28 AM
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Thanks again. Can any one suggest a transformer in the range suggested, or a website? I done some quick searching and have had no luck.

Mark
 
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Old 09-26-08, 07:08 AM
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This is the sort of transformer that you need: http://www.grainger.com/Grainger/items/2CL93 Of course, Grainger is probably not the place to buy it; but the info should help you in your search. I've not priced these out recently, and it seems that the cost would negate any benefit from buying the 'wrong' heater used. You probably want to investigate further before buying anything; it may be that this 208V heater has heating elements that can actually be connected for 240V, but the motor is 208V only, or some other work-around, or it may be that getting 208V is simply not worth it.

-Jon
 
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Old 09-26-08, 08:57 AM
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Thanks for the reply. That's what I wanted to understand. Would the cost of a transformer negate the price savings of the 208V heater.

Mark
 
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Old 09-26-08, 09:13 AM
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Thanks for working with me on this. I have one more question. It was suggested below that a 1.5kW transformer is needed. Would it be safer to go with a higher wattage transformer? I found this website: http://www.popularelect.com/index.ph...FSCysgodNFCwFg.
Where the difference between a 1.5kW and a 3.0 kW is $20.
 
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Old 09-26-08, 09:38 AM
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For your application, a higher wattage transformer couldn't hurt.

The site that you linked showed 240V to 120V transformers, which are the wrong voltage to do the job. These also may be 'isolation' transformers, with primary and secondary windings forming separate circuits. If the same company sells the correct voltage transformers at good prices, then they might be the way to go.

For your application, you would use a 240V to 32V transformer, connected in what is known as a 'buck' configuration. This lets you use a 1.5KVA transformer to power a 7.5KW heater. If you were to use an isolation transformer, you would need a 7.5KVA transformer.

-Jon
 
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