Using an electrical Inlet

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  #1  
Old 07-10-07, 08:56 PM
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Using an electrical Inlet

I am framing out my basement home theater that will have a projector attached to the ceiling. I have a question out running an electrical "inlet" on the ceiling. I want the projector to be protected by my UPS system so I was thinking about using the following

Leviton 15A 125V 2-Pole, 3-Wire Weatherproof Inlet on Flush Mount Wall plate with Aluminum Cover

(http://www.telephonestuff.com/Catalog/Model_4937.htm)

Basically, I was thinking about the following setup

House power --> UPS --> inlet --> outlet --> projector

The inlet will be connected to the outlet with EMT running 3 12 AWG wires.

Any thoughts or suggestions?


Thanks
 
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  #2  
Old 07-10-07, 09:05 PM
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That looks acceptable to me, but I am not a code expert.
 
  #3  
Old 07-11-07, 02:15 AM
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I don't think you should do this. What about getting one of the recessed wall outlets for clocks and just mounting the UPS with the projector?

You shouldn't hard wire an appliance into your electrical system. The ups you are probably considering is considered way more disposable than say a load center or junction box. Unless it is UL listed for that application, I wouldn't do it. You always have to consider what would happen if someone else came along, would they understand what is happening?

As an example, my brother-in-law and I spent many weekends working on his house so he could get an occupancy permit. The inspector found that the previous owner had used lamp cord in going through walls and other conveniences. It quickly became a game of undoing, continuity testing, and correcting.
 
  #4  
Old 07-11-07, 07:11 AM
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i like it

You prolly have a high value bulb in that projector that could stand the protection. I tend to think 14AWG is fine, and what about the sound system? That way, you can be even more tolerant of supply dropouts. You might consider an isolated ground recept, since the wiring would not run back to the panel, and it would identify the UPS outlet as "special".
 
  #5  
Old 07-11-07, 07:14 AM
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The whole point of using an 'inlet' is that the UPS remains cord connected to the circuit being supplied.

Loosegroove could probably have written the description as:
house power-> receptacle -> cord -> UPS -> cord -> inlet -> wall wiring -> receptacle -> projector

I recall a discussion on exactly this sort of install on a professional electrician's discussion board:
http://www.electrical-contractor.net/forums/ubbthreads.php/ubb/showflat/Number/42844/page/0/fpart/1
(wow, not bad, remembering something from 3 years back)

You will note the arguments against this installation because it uses flexible cord as part of the branch circuit, as well as arguments for this installation, including my own and someone describing the use of inlets to connect UPS systems.

For what its worth, the method that you describe is something that I would consider for my personal use if I wanted to UPS protect a circuit with a large UPS. If you have a receptacle and an inlet, and use cord to connect a UPS to both of these, then the cords are not acting as the 'fixed wiring of a structure', but are instead used to connect a piece of equipment (the UPS). I would wire the inlet and outlet in the same box, and would make sure that the _ground_ was continuous without the UPS connected.

However UPS units are now so small and cheap that it is probably simpler, cheaper, and less apt to confusion if you just put a small stand-alone UPS right up next to the projector.

-Jon
 
  #6  
Old 07-11-07, 07:17 AM
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Isolated grounds are useless and a waste of money in a residence.
 
  #7  
Old 07-11-07, 07:49 AM
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The link winnie provided talks much more about the code issues. In my non-professional opinion, what you're looking to do sounds safe and reasonable. You may want to contact your electrical inspector - if you're having it inspected, he'll have the final say regardless.

I'd consider using a 15A twist-lock inlet so you don't have to worry about the plug getting pulled out or falling out over time.
http://diallighting.thomasnet.com/item/wiring-devices/wiring-devices-twist-lock/lev4716c?&seo=110
I would keep the neutral and grounds separate - as in not tied in to anything else. Basically you're making a "hard-wired extension cord".

I'd also suggest the use of NM-B wire instead of EMT. Much easier - but you may of course have a reason for using EMT.

If all else fails, you can forget the whole thing and get a small UPS and mount it right next to the projector.
http://apcc.com/products/family/index.cfm?id=21

Good luck!

(ps: let us know what you decide to do - I'm sure as projectors and flat panel TVs are used more often, more people will have similar questions)
 
  #8  
Old 07-11-07, 08:14 AM
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I have this exact set up in my own house, and it works just fine. I keep my bulky 1400 VA UPS in the basement and have computers in two rooms powered from it using an inlet wired to dedicated receptacles.

> would wire the inlet and outlet in the same box, and would make sure
> that the _ground_ was continuous without the UPS connected.

I second this recommendation. Use a two gang box with the UPS receptacle on one side and the inlet on the other side. Not only does this allow you to interconnect the grounds, but when you move out it's a simple matter to remove the inlet and hardwire feed to the projector receptacle.
 
  #9  
Old 07-11-07, 11:06 AM
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I still don't like it

Even though ipbooks and racraft (two members with way more experience than me) don't see a problem, I do. I work in IT and we have this nonsense called six sigma. It one of those process improvement ideas designed to make contractors rich and projects crawl. But the one good idea is the removal of the hero mentality. We're forced to look at our groups and figure out what happens if this guy gets hit by a bus and isn't here tomorrow, can the business line continue? Ive seen electricians on this board claim that they can plug a generator in to a dryer receptacle because "I know how it works." Well, how is someone supposed to figure this inlet outlet nonsense if you leave it as you're saying? When I kill a circuit, I want it dead. I wouldn't expect that in a closet or suspended ceiling, or accessable but hidden area that someone hid a UPS. Sure, I might hear the beeping, but you're still running current on a circuit that has been turned off.

I guess I'm still mad about the nonsense house I posted above and the several Saturdays of figuring out why the crazy old previous owner thought lamp cord was the only way to run circuits.

You're still going to do what you want, but please put a note on the breaker in case you get hit by a bus.
 
  #10  
Old 07-11-07, 11:10 AM
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Actually, I have not weighed in on the overall plan.

I won't say much, because it has already been said. However, I will say this:

If you in any way use a UPS to feed into house wiring, please make a note in your panel and on the receptacles that the UPS feeds. Something small for the receptacles like "Fed by UPS" or something similar is in order.
 
  #11  
Old 07-11-07, 11:17 AM
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I consider the points made by racraft and Fubar411 to be quite good. I've made my _code_ argument (that this is acceptable if done properly), but just meeting code is not necessarily good design.

I believe that it would be good design to put this UPS in a location that makes it obvious that it is part of the circuit. This could mean, for example, putting the UPS right next to the load served (thus not wired in to the circuit), or putting the UPS next to the panel that serves the circuit. This way, if you flip off the breaker you will know right away that there is still something on that circuit. It might mean putting the UPS in the same room as every exposure of the circuit in question, or something else that makes the UPS obvious.

I believe that putting the UPS somewhere non-obvious is code legal...but poor design in the same way as providing GFCI protection to your garage with the receptacle on the front porch.

-Jon
 
  #12  
Old 07-11-07, 01:03 PM
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you guys are loosing me

the poster has a ceiling projector in a finished room. common sense would dictate that the UPS will not reside on the ceiling... So, it's either an extension cord or built-in wiring. He wants to do built-in wiring, which is a good idea, of course, if done properly.

The talk of buses (or was it busses), GFI, 6-sigma, breaker boxes, continuous grounds, its all outside the scope of the question.

Most IT equipped buildings (and i'm in one now) have in-building UPS 120v runs. Does this shock anyone?? My desk has these partitions with built-in POCO AND UPS recepts, with some cryptic color dots trying to label them. But that's a bit off of the point.
14-3 tnnh in conduit, he is good to go. Off to the next job.
 
  #13  
Old 07-11-07, 04:58 PM
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There is a huge difference between the UPS I have sitting next to my desk and the UPS systems in an office.
 
  #14  
Old 07-11-07, 08:55 PM
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Winnie is exactly correct with describing my plan. It sounds like it will pass code, but I will probably have my electrician neighbor look at it before I put up the drywall.
Those buses in Chicago are crazy so I will probably make a note on the service box about this special receptacle. Also I will probably try to find a receptacle with the orange triangle painted on it that which my office uses to designate UPS outlets. Once everything is complete I will take a picture of my handy work. I enjoyed reading all of the advice.
thanks
 
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