What size wiring for Central A/C compressor?

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Ok ,guys. Now something just came up . I know we are up to 51 posts for this thread already, and I was not sure whether to continue this one, or start a new one, but anyway:
My friend had an idea if he had gotten a generator one day, he can utilize the A/C disconnect panel outside to backfeed into the main panel. Of course he would shut off the main breaker and pull the A/C disconnect when he did this.
I can put an outdoor twistlock outlet next to the A/C disconnect panel, and put a short nipple between them an connect the wiring.
But I cannot do this with the existing 10 guage wire since it is the old 10/2 stuff with a small ground on it. I would need to run an 8/3 with gnd ( 2 phases plus neutral).
I know this is not the right way to backfeed a panel, but regardless, does it make sense now to run the 8/3 ?
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I'd leave the AC wire alone, and wire a power inlet. You'd be wise to make some kind of transfer switch to make it idiot resistant. During a high stress power cut, it's easy enough to forget a step or two in the procedure.
Christopher A. Young Learn more about Jesus www.lds.org .
I know this is not the right way to backfeed a panel, but regardless, does it make sense now to run the 8/3 ?
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If you know it's not the right way, then why are you proposing to do it? Why take an AC circuit that is 100% legal nd safe as it is and turn it into something to be used as a dangerous code violation? If he wants a generator connection, install an inlet outside and run it to a proper interlock device installed on the main panel. If the panel maker doesn't have one, then try:
http://www.interlockkit.com/
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wrote:

That is an excellent invention. I did not even know those interlocks existed. A little pricey at $150, but I'll definately consider it. The only issue is finding space in the main panel for an extra double pole breaker for the generator, but I can use some twins here and there on lighting circuits to to free it up.
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On 3/8/2013 8:30 AM, Mikepier wrote:

The interlock kit trader4 showed you is the least expensive "safe" way to do it but before that product was available I used a double throw safety switch and sub panel or put it between the lighting panel if it was separate from the a main panel with the heavy loads. Of course you run a separate line outdoors to your portable genset and depending on its capacity you will have to choose which loads to turn off/on as needed. ^_^
http://www.homedepot.com/p/t/100151733?productId0151733&storeId051&langId=-1&catalogId053&cpncode0-126902591-2&srccode=cii_10043468&cm_mmc=shopping-_-shopzilla-_-D27-_-100151733
http://tinyurl.com/a9fqckb
TDD
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On Mar 8, 10:01 am, The Daring Dufas <the-daring-du...@stinky- finger.net> wrote:

So that double throw switch has to be put between the main panel and subpanel, (where the subpanel would have the essential circuits in them to run off generator) , right?
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On 3/8/2013 9:31 AM, Mikepier wrote:

Exactly. Sometimes there is a separate lighting panel which will have loads like wall outlets, furnace blower, kitchen, bathroom, etc with the heavy loads in an outdoor breaker box below the power meter and a large breaker feeding the indoor panel. Sometimes a separate panel with the heavy loads could be indoors next to the lighting panel. It depends on your setup but if there is only one main panel that is not the split variety (another variation) you can get a sub-panel which will use the same type breakers you have so you save money on breakers. I had my local inspector tell me it was OK the use the old panel as a junction box to splice your circuits for the sub-panel if the wires/cables were too short to move over to the sub panel. Don't forget the knock out blank inserts to fill in the openings for the removed breakers. ^_^
TDD
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On Mar 8, 12:08 pm, The Daring Dufas <the-daring-du...@stinky- finger.net> wrote:

Lets's go one step further. By any chance do they make double throw circuit breakerss? So if one wants to wire up just the essential circuits ( heat, light, etc), there would be 2 terminals on the individual breaker: one for normal power and one for generator. That way you just flip the breaker and it will switch to the generator side.without having to worry about shutting off the main.
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On 3/8/2013 11:19 AM, Mikepier wrote:

I'm sure someone manufactures a molded case high current switch like that but I haven seen one and I don't know of one that would have built in over-current protection. ^_^
TDD
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It would have to be not only a unique breaker, but also a unique panel to accept said breaker. It doesn't exist for some very good reasons. And if it did, what do you think that special panel and those special breakers would cost compared to the simple alternatives?
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Mikepier wrote:

Just an observation, but none of the devices offered on this website are UL approved. They claim to meet "all NEC requirements for optional standby systems (Article 702)," but that's easy to say.
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They go a bit further than that. They have the test reports that show that they have been tested for use as accessories with UL 67 listed panelboards. What exactly that means in regard to making them code compliant when put on a panel, I don't know. This issue is why I recommended going with an interlock from the actual panel manufacturer, if one is available. That way you know there is no issue. From some discussions I've seen online it looks like people are using the Interlockit product. How many of those are actually inspected, do some inspectors have issues with it, IDK. Given that it's just a piece of metal, has no direct involvement with the electricity, obviously does what it' intended to do, I'd have no problem using it from a safety standpoint. But it would be a bitch to buy it, install it and have it rejected. I guess best thing would be to take a print out of the info, including their test report, over to the inspector and ask before buying. Especially if you're in an area that tends to be tougher.
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On Sat, 9 Mar 2013 07:13:47 -0800 (PST), " snipped-for-privacy@optonline.net"

I have mixed emotions on the interlock deal. I have seen some shop built ones that are better than the Square D model but it is still not listed. Legally I would have to reject it or "own" it (article 90-4). I might tend to owning it personally but that decision is reall;y up to my boss if I worked for a municipality,.
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On 3/9/2013 5:09 PM, snipped-for-privacy@aol.com wrote:

http://www.interlockkit.com/warranty01.htm "Tested for use with UL 67 Listed Panelboards Ref. Wyle Laboratories Test Report T52431-01 Wyle is a Nationally Recognized Testing Laboratory authorized by OSHA for UL standard 67 and recognized by all 50 US States."
report from Wyle Laboratories http://www.interlockkit.com/MasterElectric5243101.pdf "Representative samples of the product covered by this report have been evaluated and found to be suitable for use with UL 67 listed panelboards provided the Conditions of Acceptability are met." The "Conditions of Acceptability" are included - generally installation by someone who is not an idiot.
I wouldn't bet UL standards envision testing devices made for other electrical manufacturers products (other than "classified" breakers).
Would Wyle give you enough cover? Any opinion of whether other inspectors are likely to accept it?
More generally, what is the acceptance of NRTLs (other than UL and the former FM) for electrical approval? (The OSHA process is OSHA has a list of standards - mostly UL for electrical. And it has a list of NRTLs. NRTLs are individually qualified for each standard they are allowed to approve for, for OSHA. I kinda remember Los Angeles does the same thing.)
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wrote:

uh ... not so much
Organizations Currently Recognized by OSHA as NRTLs
Canadian Standards Association (CSA) (also known as CSA International) Communication Certification Laboratory, Inc. (CCL) (DBA Nemko-CCL, Inc.) Curtis-Straus LLC (CSL) FM Approvals LLC (FM) (formerly Factory Mutual Research Corporation) Intertek Testing Services NA, Inc. (ITSNA) (formerly ETL Testing Laboratories, Inc.) MET Laboratories, Inc. (MET) NSF International (NSF) QPS Evaluation Services Inc. (QPS) SGS U.S. Testing Company, Inc. (SGSUS) (formerly U.S. Testing Company, Inc./California Division) Southwest Research Institute (SWRI) TUV Rheinland PTL, LLC (TUVPTL) TÜV SÜD America, Inc. (TUVAM) TÜV SÜD Product Services GmbH (TUVPSG) TUV Rheinland of North America, Inc. (TUV) Underwriters Laboratories Inc. (UL)
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On 3/10/2013 10:49 AM, snipped-for-privacy@aol.com wrote:

The report from Wyle is dated November 2009. According to OSHA, Wyle was a NRTL until August 2011 and one of the standards they could test for was UL 67.
So is the report still valid?
If it was valid when issued in 2009 does that give you a cover?
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On 3/9/2013 8:19 AM, HeyBub wrote:

They usually show up when threads get into connecting generators to the house panel. Last time was probably November.

You can add a subpanel and move some of the loads to it.
Panels will have a limitation on where you can install half-sized breakers. It may be in all positions, no positions, or anywhere in between. The label will tell you. Half-size/twin breakers (in general) can only be installed where the label says they can.

http://www.interlockkit.com/warranty01.htm "Tested for use with UL 67 Listed Panelboards Ref. Wyle Laboratories Test Report T52431-01 Wyle is a Nationally Recognized Testing Laboratory authorized by OSHA for UL standard 67 and recognized by all 50 US States"
Depends on whether your AHJ recognizes Wylie. There is probably not a clean way to get these interlocks listed for other manufacturer's panelboards. But they are a mechanical device that does not have electrical ratings - likely they are OK. Ask the AHJ.
Several manufacturers (including SquareD and Siemens) have a similar mechanical interlock for their panels.
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On 3/8/2013 8:51 AM, Mikepier wrote:

Hay bailing sounds great and of course he will never forget, be sick, not there and someone else needs to do it or whatever.
What you described is simply hay bailing instead of using conventional common methods.

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On Tue, 5 Mar 2013 17:20:50 -0800 (PST), Mikepier

Typically 60a but there is no over current protection, as you note. That is just what the contacts will handle,
It is always best to trip the breaker before you pull the disconnect. (arc flash) The disconnect is just for the safety of the workman so he is sure he won't get killed if someone turns the breaker back on.
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On Mar 4, 5:55 pm, The Daring Dufas <the-daring-du...@stinky- finger.net> wrote:

This is interesting stuff guys. I never knew there were a different set of codes for motors and A/C's. I'll leave the existing wiring for now. What I'll do is run a drag line in the ceiling joists so if i ever had to run another line, I can do it easily by pulling the new wire attached to the drag line.
I have another question regarding central Vac systems wiring requirements. Please see upcoming seperate post.
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