Getting ready for Hurricane Isaac

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  #1  
Old 08-28-12, 05:30 PM
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Getting ready for Hurricane Isaac

Greetings,

I am preparing for Hurricane Isaac and obtained a room Air Conditioner today that I'll connect to my generator in case power goes out. Of course the A/C plug 6-15P (240v/13amp) does not match the generator outlet L14-30R (250v/30amp) - both pictured below. The generator does also have four 110v/20amp outlets available.

I obtained a plug to match the generator (Hubbel L14-30P) and thought I would simply replace the A/C plug but see several issues.

1. The A/C plug has a built in LCDI device, the Hubble replacement does not.
2. The A/C power cord will only allow for approximately 18-24" of reach. Naturally, the generator will be outside at least another 4-6 feet away.
3. The A/C plug has 3 wires and the replacement plug asks for four wires.

Any ideas on how I can get the A/C working should I need it?

Thanks,
Pern


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  #2  
Old 08-28-12, 06:03 PM
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Make up an adapter one end female to receive the male AC plug and the other a male to fit the generator. The neutral would not be used.
 
  #3  
Old 08-28-12, 06:24 PM
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When Ray writes "adapter" I think he really means make an extension cord long enough to reach from the generator to the A/C unit. Put the NEMA L14-30 plug on one end of the three-wire cable and a NEMA 6-15 connector (single receptacle for a cord end) on the other end. Technically the cable should be no less than #10 copper to match the circuit breaker on the generator but since it will ONLY feed the A/C a smaller gauge is acceptable but I would not go smaller than #12.

The other possibility, a better one in my opinion, is to use a #10, four-conductor cable coming to an inexpensive four-circuit circuit breaker panel. Install one 240 volt, 15 ampere circuit breaker and a NEMA 6-15 single receptacle for the AC and then add two 15 ampere 120 volt circuit breakers going to two standard 120 volt receptacle for other items in the house and forget about using the 120 volt receptacles on the generator.
 
  #4  
Old 08-28-12, 06:45 PM
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Yes, an extension cord if he does not have a four wire cord for the generator. If he does already have a four wire cord than an adapter a foot long would be enough.

I like Furd's idea even better but mine is simpler.
 
  #5  
Old 08-28-12, 07:08 PM
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Thanks to you both for your ideas. I am a relative novice in the area of electrical work. I was able to follow along with the extension cord idea though I don't know which prong should receive which wire on the NEMA L14-30 plug...especially when it calls for four wires?

If I were to go the suggested "better route", where would you suggest positioning the inexpensive four-circuit breaker panel? I'm having difficulty picturing that in my mind? I suppose that could be positioned inside near the A/C and I would run a cable from that panel (using #10 wiring as you suggest) using the already purchased matching plug to plug into the 30amp receptacle on the generator. And if I'm reading correctly, you're describing having a receptacle that matches the current A/C plug connected to the panel as well as the other two 120's you also mentioned.

So the panel is powered by the generator, and the A/C and two other appliances would be powered by the three receptacles somehow connected to the panel. Am I getting close to what you're describing?
 
  #6  
Old 08-28-12, 07:57 PM
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I don't know which prong should receive which wire on the NEMA L14-30 plug...
The one you don't need, the neutral, should be silver. Regardless, it is opposite the ground, which is the one with one edge turned up. The other two prongs are the two hots, and it doesn't matter which is which.
 
  #7  
Old 08-28-12, 08:13 PM
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The sub panel would be mounted to a piece of 3/4" plywood large enough to all hold the panel and three receptacles. Conduit nipples would connect the receptacle boxes, metal handy boxes would be okay, to the panel and wiring between the panel and receptacles would be done with individual conductors, (THHN/THWN). #10 4-conductor SOW cord would be attached to the panel to run to your generator where it would plug in. The temporary power supply, which is what this is, could be laid on a table or temporarily hung on a wall near enough to the AC to plug the AC into it.. Extension cords to your 120 volt loads would be plugged into the 120v receptacles on the temp power supply.
 
  #8  
Old 09-03-12, 07:06 PM
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Update - fortunately our power never went out so we did not need to connect the window A/C. However, I have nearly completed the sub panel project (in preparation for the next storm!) and have a final question.

I did secure 10/3 romex and will use that to connect between the generator and the sub panel. Though I'm not sure how to make the connections within the sub panel. I know where the white wire connects. But do the black and red wires get connected to the hot lugs in the sub panel? Also, in the L14-30P plug, it's obvious where the ground goes (green screw). How about the other 3 wires? Which screws should be used for the red, white, and black?

Thanks!
 
  #9  
Old 09-03-12, 07:37 PM
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Type NM (Romex) cable is not suitable for this project, you need a flexible cable such as SOW or SJOW.

Yes, the black and red wires connect to the "hot" lugs in the small panel. The reds and black wires connect to the x and y connections in the L14-30 plug and the white to the n connection.
 
  #10  
Old 09-03-12, 07:52 PM
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Thanks for responding and for the tip on SOW or SJOW. I've never heard of that. Where would I find that type of cabling?
 
  #11  
Old 09-03-12, 08:14 PM
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Where would I find that type of cabling?
Home store or hardware store. I is a very common item.
 
  #12  
Old 09-03-12, 09:58 PM
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Type S (plus other letters) cable is normally sold by the foot from the spools where the rest of the "sold per foot" wire and cable is found at the mega-mart homecenter. I suggest not getting any cable that has the letter T in the designation. T means plastic insulated and will be less flexible than the rubber insulated. Be sure that it does have a W for water resistant.
 
  #13  
Old 09-04-12, 08:04 AM
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Furd, Ray, and others,

Thanks for your coaching and input. It has been very helpful. I have one final question (I hope). Please take a look at the photos of my sub panel. There is not an obvious place to attach the grounding wires within the box. What's the best course of action?

Thanks again!

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Old 09-04-12, 08:22 AM
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That panel needs an auxillary ground bar purchased separately. The label inside the panel will show you where it mounts and the part to purchase.
 
  #15  
Old 09-05-12, 10:26 AM
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this panel will NOT work for a 240v air condtioner unless her were to main lug the outlet for the ac and use ther breakers for the 120v
 
  #16  
Old 09-05-12, 10:52 AM
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Unfortunately he's right. That's why Furd told you to get a "4 space" panel. That's a 2 space/4 circuit box. There's a difference. The A/C is straight 240v, which (yes it sounds odd) does not have a neutral. The two flat prongs are both hot (red and black) and the round prong is ground. A 240v breaker takes up 2 spaces in a panel. The 'double' breaker that you have in there is called a 'tandem'. You only get 120v out of it, and if you try to hook a 240v appliance to it, it won't work.

The best thing you can do is try and return that box, and get a 4 space/8 circuit one. It will have spots for 4 separate breakers.

Otherwise, if it can't be returned (since you knocked out the knockouts) your only option is called a 'quad tandem' breaker like this.



It fits in two breakers spaces, but it has three separate circuits.. Two 15A/120v and one 20A/240v. Notice the two center breakers are tied together? That's a 240v. It connects to both the red and the black legs of the generator. You also have one of the 15A breakers on the red leg and the other on the black leg to help balance the load.

Unfortunately quad tandems are expensive.. Upwards of $60-80. So that's why you should try to return what you have and get the proper panel. It'll cost you less in the end.
 
  #17  
Old 09-05-12, 12:23 PM
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If its unreturnable he should be able to connect the ac outlet directy and use the 120v breakers for the other outlets IMO its the same as the extension-cord-adapter option
 
  #18  
Old 09-14-12, 06:16 AM
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Almost finished this project!!!

OK folks, I replaced the panel, obtained the ground bar and installed, and obtained the correct 240 volt breaker that will use two spaces on panel.

Another question, does it matter which hot screw (breaker half) is used to connect the 240 volt breaker to the Air Conditioner outlet?

Thanks,
Pern
 
  #19  
Old 09-14-12, 06:22 AM
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Never mind...I just read JerseyMike's post again and I won't be using a white/neutral conductor. If I read correctly, it will be a black or red conductor from each of the 240 volt hot screws to the hot screws on the AC outlet.

If I'm incorrect, somebody stop me!

Thanks everyone!
 
  #20  
Old 09-14-12, 07:20 AM
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I am not comfortable with Breather 3's solution. If you do it that way best would be to connect the red and black of the incoming SOW cable to two pigtails for each wire using wire nuts and then one pigtail of each color to the AC receptacle and one pigtail of each color to the box lugs. This is because the box lugs are probably not designed for two wires. If at all possible it is better to get the correct box. If you can't return it maybe you can sell it on Ebay.
 
  #21  
Old 09-14-12, 07:27 AM
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I did get the correct box and a 240 volt/20 Amp breaker (which connects to two spaces in the new box). Will I be connecting correctly based upon my previous post?
 
  #22  
Old 09-14-12, 10:22 AM
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I just read JerseyMike's post again and I won't be using a white/neutral conductor. If I read correctly, it will be a black or red conductor from each of the 240 volt hot screws to the hot screws on the AC outlet.
If you're referring to this:
Originally Posted by JerseyMatt
The A/C is straight 240v, which (yes it sounds odd) does not have a neutral. The two flat prongs are both hot (red and black) and the round prong is ground.
then yes, Matt did say "red and black" for the two hot wires feeding the receptacle for your A/C. But he also said "The A/C is straight 240v, which... does not have a neutral."

That means that you only need three wires, and only two of those are current-carrying conductors. You can connect the breaker to the receptacle with XX-2 cable, which does not have a red wire. Since you don't need the neutral, you can redesignate the white wire as carrying ungrounded current by permanently marking it, on each end, with electrical tape or a permanent marker. I would use red, but it can be any color except white (duh), gray, green or yellow/green.

If you said what size your 2-pole breaker is, I missed it. The XX in XX-2, above, needs to be 14AWG on a 15A breaker, 12AWG on a 20A, and 10AWG on a 30A.
 

Last edited by Nashkat1; 09-14-12 at 01:26 PM.
  #23  
Old 09-14-12, 03:00 PM
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I am confused. I thought you were wiring the receptacles with THHN/THWN wire through nipples to the receptacle boxes. Am I wrong?
 
  #24  
Old 09-14-12, 03:17 PM
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I thought you were wiring the receptacles with THHN/THWN wire through nipples to the receptacle boxes.
If I misunderstood and this is the wiring method you're using, then you need a black, a red, and a green wire to your A/C receptacle. No white.

My advice in post #22 applies only if you're using cable.
 
  #25  
Old 09-14-12, 08:02 PM
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Originally Posted by ray2047 View Post
I am confused. I thought you were wiring the receptacles with THHN/THWN wire through nipples to the receptacle boxes. Am I wrong?
If you look at his picture, he ran Romex through short pieces of ENT.
 
  #26  
Old 09-14-12, 08:13 PM
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If you look at his picture, he ran Romex through short pieces of ENT.
That picture is of the panel he returned. I have no reason to imagine that he did it any differently after he got the new panel though.

Pern3: No bare conductor in conduit. You need to remove the Romex, if that is what you have, and replace it with individual insulated conductors.

Good spotting, Matt.
 
  #27  
Old 09-14-12, 08:49 PM
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Saw the ENT didn't see the NM-b. I do now. Part of the problem when you know how to do it you don't look for what you don't expect.

I originally wrote in Post#7:
and receptacles would be done with individual conductors, (THHN/THWN). #10 4-conductor SOW cord would be attached to the panel to run to your generator
But initially you used 10-3 NM-b and I didn't catch it. Now I see you used NM-b instead off the THWN I recommended. I did notice you used ENT instead of nipples.

Pern, not being mean but you really need to read the instructions we give more carefully and ask if you don't understand. We don't mind you asking for more detailed explanations. You need to check with us before making substitutions. If you asked for help at BigBox and was given those suggestions you now know they can't be relied on.
 
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