120V receptacle without adding additional transformer and panel

[hbiss]

And as for the cost - in respect to the job size the expense to do it right is so minimal that it wouldn't be noticed.

If the extra cost wouldn't be noticed then I say do it.

-Hal

 

[fmtjfw]

I don't know of anyone applying that section to a simple unit heater

I read 210.63 as "heating, air-conditioning, and refrigeration". I think it was poorly written to show the real intent. Notice "and" rather than "or". I think the intent is to provide a receptacle for a vacuum pump that can be required for some types of maintenance to HVAC & Refrig. equipment that uses compressible gases in its operation. Simple resistance heaters have no need for vacuum pumps. I think you could request a ruling before you add a transformer and all that that entails.

 

[kwired]

I read 210.63 as "heating, air-conditioning, and refrigeration". I think it was poorly written to show the real intent. Notice "and" rather than "or". I think the intent is to provide a receptacle for a vacuum pump that can be required for some types of maintenance to HVAC & Refrig. equipment that uses compressible gases in its operation. Simple resistance heaters have no need for vacuum pumps. I think you could request a ruling before you add a transformer and all that that entails.

I agree on your analysis of what the intent of 210.63 probably is. But as is worded, any heater would fall under this rule, even a panel heater, pipeline heating cable, immersible tank heaters, or embedded radiant heating cables.

210.64 is new in 2014, but I don't agree it is necessary at all services.

Irrigation equipment being the one I run into - other remote pumping stations however would be similar. If 120 volts is readily available I don't have as much issue with providing a receptacle and probably would have before this was required anyway, but the cost of a transformer to provide a 120 volt receptacle is pointless when the guys that service this kind of equipment almost always have portable generators on their service trucks anyway. JMO.

 

[cpinetree]

Thanks for the info! I'm aware that you always need a transformer to change voltages. My thought of having one on the unit heater was that it would be one less step I had to take because it would be inside the pre-fabbed unit. All I would have to do is wire the unit heater up and I would meet my requirement for a service receptacle.

Anyway - I looked up the free standing circuit breaker you referenced. Everyone seems to be calling them "Unit Mount C/Bs". I looked for images, but I don't see how they are usually mounted. Is there a common small enclosure that is typically used that would (in this case) sit next to the secondary of the small wall mounted transformer? I'm thinking something similar to a molded case cb.

They mount to DIN rail or with supplied ears (can be bottom mounted or top mounted).
I do not think you will find a pre made enclosure as these are usually oem, with that said I am pretty sure you can adapt a Squared D 2 circuit enclosure to work for you.

See this pdf: http://download.schneider-electric.com/files?p_Reference=0720CT9401&p_EnDocType=Catalog&p_File_Id=1664274475&p_File_Name=0720CT9401R105.pdf

 

[Jraef]

Thanks for the info! I'm aware that you always need a transformer to change voltages. My thought of having one on the unit heater was that it would be one less step I had to take because it would be inside the pre-fabbed unit. All I would have to do is wire the unit heater up and I would meet my requirement for a service receptacle.

Anyway - I looked up the free standing circuit breaker you referenced. Everyone seems to be calling them "Unit Mount C/Bs". I looked for images, but I don't see how they are usually mounted. Is there a common small enclosure that is typically used that would (in this case) sit next to the secondary of the small wall mounted transformer? I'm thinking something similar to a molded case cb.

So what I would do is buy a vented NEMA 1 enclosure (assuming indoor here) big enough to house a cheap little transformer like a CPT plus one of those little Sq. D QOU breakers, mounted so the handle comes out through a hole (the brackets for them allow that).


http://www.mouser.com/ds/2/177/1416-746369.pdf

First though, you have to decide on how much power you want to give them. A 500VA CPT will give them about 4A, enough to run a small drill motor but if you want to run a good one like a Milwaukee, it will want 8A, so 1000VA minimum. That will take a larger box. Whatever you decide, you just nipple an outlet box to it and put in a single receptacle (not a duplex) with a nameplate telling the user what the limits are.

 

[GoldDigger]

There is a good chance that a vacuum pump for refrigerant recovery will draw more than that. Not relevant to the OP's case, but more general.

 

[ramsy]

Just dump 5700 feet of #14 wire into Rubbermaid 50-Gal trash can.
Bring #14 from 1-Pole 15A breaker in 277/480Y panel --thru 5700ft of wire-- to 120v receptacle, then 3ft back to neutral bus.
Sticker above receptacle reads 5-Amp only, anything less blows up whatever's plugged in here.:lol:

 

[iwire]

210.63 requires a 15 or 20 amp receptacle be installed at HVAC equipment

210.21(B)(3) requires those receptacles to be supplied with a minimum 15 or 20 amp branch circuit. (Unless you use a single but then GFCI protection gets a bit tricker)

Therefore in my opinion the minimum size transformer would be 1.8 or 2.4 kva respectively.

We remodeled a large department store and each of the thirteen RTUs had a 0.75 or so transformers for the outlet without proper OCP. During the remodel the roofers smoked almost all of them trying to run large power tools from them.

We got a large extra to run 120 volt circuits to each RTU to fix the situation.