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Onan 3 wire to 4 wire Transfer Switch Recepticle


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  #1  
Old 02-21-2017, 10:05:11 PM
echolake1 echolake1 is offline
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Default Onan 3 wire to 4 wire Transfer Switch Recepticle

I have an Onan genset 5.0 with three wires coming from it. One black hot white netural and green gnd. I have a powermate six breaker transfer switch with a four wire plug. Red hot Black Hot green Gnd. white Netural I want to connect this onan to my two service panel connections. Can I take the Black Hot from the Onan and "Y" it off with two 6gauge wires wire nutted together making it one hot from the onan to two wires 120v each from the same onan hot wire to connect to my service panel lugs as long as I disconnect the MAIN breaker to give me 120V. The transfer switch is set up for red wire three breakers and the other three Black wire.
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Old 02-21-2017, 10:19:40 PM
Wayne 440 Wayne 440 is offline
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Default Re: onan 3 wire to 4 wire transfer switch receptical

Are you asking if it is possible to do this or if it is advisable to do so?

If the former, yes. If the latter, no.
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Old 02-21-2017, 11:16:05 PM
TLB01 TLB01 is offline
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Default Re: onan 3 wire to 4 wire transfer switch receptical

I have done this. It works. I have fed my 30 amp transfer switch with a Honda EU1000 this way. . I did it a little differently by buying heavy duty 15 amp extension cord, cutting off the female end and putting a 30 amp twist lock end in its place. There is a jumper in the plug that jumps the black to the red blade on the twistlock and thus feeds both sides of the transfer switch with 120 volts. My transfer switch is set up for 120 only, if that makes any difference.

Doubt the NEC likes it. Most walkers of the electrical straight and narrow will turn you into a pariah for doing it and may do their utmost to discourage you...if not outright lambast you. Doubt your homeowners insurance will pay a claim if this turns out to be the direct cause of an accident or loss.

Proceed at your own risk.
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Old 02-22-2017, 01:00:33 AM
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Billy J Shafer Billy J Shafer is offline
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Default Re: onan 3 wire to 4 wire transfer switch receptical

That is called the costing yourself allot of money. When something goes wrong method.
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Old 02-22-2017, 01:08:33 AM
Steve Dawkins Steve Dawkins is offline
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Default Re: onan 3 wire to 4 wire transfer switch receptical

Quote:
Originally Posted by echolake1 View Post
I have a powermate six breaker transfer switch with a four wire plug.:
Does your transfer switch have six switches with GENERATOR-OFF-UTILITY positions for each switch, and a red and black wire for each switch? If so, this type of transfer switch isolates branch circuits from utility power and you don't have to turn off the main circuit breaker. Of course, it's always a good idea to turn off the main for extra safety.

If your 5kW generator has only 120 volts output, it is capable of producing 41.6 amps. The inlet plug on your transfer switch is rated 30 amps. As mentioned previously, you can install a jumper for the hot wires on the twist-lock connector from the generator. You probably won't be exceeding 30 amps on each hot. HOWEVER, you could easily exceed the 30 amp rating on the neutral, which will cause it to overheat. Not only are the twist-lock inlet plug and mating generator connector rated at 30 amps, but the white neutral wire in the transfer switch that connects to your house panel is also rated for 30 amps. (#10 AWG)

Are you sure your generator output wiring can't be reconfigured for 120/240 volts, 4 wire? If you post the model and spec number of your genset, some of the smart guys here can tell if it can be reconfigured. If it can, you will be much better off to do that. Each hot and the neutral will carry a maximum of 20.8 amps. If your genset is only 120 volts, you should install a 30 amp circuit breaker or fuse on the hot wire of the generator output, to limit the current to the transfer switch's input rating.

After re-reading your post, I'm not sure what you are trying to do. Please post the model number of the Coleman transfer switch so I can look it up. Is this switch currently wired to your electric service? If you have two circuit breaker panels for your main service, you definitely SHOULD NOT try to wire this transfer switch to backfeed the panels.

Last edited by Steve Dawkins; 02-22-2017 at 01:31:11 AM.
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Old 02-22-2017, 01:35:26 AM
Doug Reed Doug Reed is offline
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Default Re: onan 3 wire to 4 wire transfer switch receptical

For a quick read about the National Electrical Code and how it applies to generators and transfer switches, you can read the "Generator and Standby Power Systems 2014" PDF from the Mike Holt web site. He does a pretty good job of explaining how it should be done. If this is for a home system, ignore sections 700 and 701 since only 220, 445, and 702 apply. He also has a number of good videos on YouTube if you want to look.
http://www.mikeholt.com/freestuff-books.php

There have been many discussions on the SmokStak site about this specific issue. Nobody is going to suggest backfeeding the house wiring as a "good" way to connect your generator. But the NEC code in section 702.4 and 702.5 does say what you must do in order to do it safely and legally. In my personal situation, I decided it could be done if I had written directions and attached the generator jumper cable to the main 100 amp fuses in the basement. In order to connect the generator I first have to unplug the fuses to take the cable out to the garage for hookup. That guarantees the home is disconnected from the power line as they specify in section 702.5.... Your solution could be different.

The Mike Holt file doesn't really provide a lot of info but it was spelled out a bit better in the full NEC manual. Somewhere it said that only "authorized personnel" can make the switch to generator, so plan to do it yourself, the wife can't do it if you're not home.... They REALLY don't want you connecting your generator the "backfeeding" way..... And even if you get the electrical inspector to agree, you may find that your homeowner's insurance will not cover you if there is a claim.

I did a quick search and found you can download a PDF copy of NEC 2014 from this link:
https://archive.org/details/NationalElectricalCode

Some people have avoided the issue completely by wiring an extra outlet box near each appliance you plan to run off the generator during a power failure. Connect the extra outlets to the junction box where you will plug in the generator. Then you unplug the appliance from the normal outlet and plug it into the generator outlet during the power failure. I'd suggest using a different color outlet and labeling it to avoid confusion..... Good luck!!
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Old 02-22-2017, 02:04:28 PM
echolake1 echolake1 is offline
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Default Re: onan 3 wire to 4 wire transfer switch receptical

Advisible it's not, I agree But would it work ? this is the question I'm looking for. It's not a normal hookup but before I got stupid I did'nt want to do it and get Really Stupid if it was wrong. (Thank You for that answer). Just don't try this with main curcuit breaker on , this part I knew just as a safety comment.

---------- Post added at 01:04:28 PM ---------- Previous post was at 12:37:39 PM ----------

My transfer switch Mod.# is a TK-65000 and it is exactly as you described it. The
Onan Mod. # 5.0BGA 3CR/16004C. Now that you asked the A.C. volts from the Onan Is 120/240 not just 120V. I have done alot of electrical But I am Not an electrical but trade. I'm asking these questions about Onan elec. hookups because I want to stay alive if you get what I mean. I know there is a way to go four (4 ) wires to my transfer switch which is a (4) wire Twistlock I'm all ears.
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Old 02-22-2017, 02:08:27 PM
len k len k is offline
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Default Re: onan 3 wire to 4 wire transfer switch receptical

Sounds like your asking if you can connect a 120 only gen to a 120/240 house , by powering both house hot leads with the same gen hot lead.

This can lead to overheating the neutral if any of your building circuits are wired as a shared neutral. Shared neutral is a branch circuit where several 120 outlets are supplied by a hot from each hot phase of 120/240 and ONE neutral. When the hots are both supplied by same phase of 120 currents in that shared neutral no longer tend to cancel , they add and can overheat the neutral. Possibly catch it on fire.

Last edited by len k; 02-22-2017 at 02:31:52 PM.
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Old 02-22-2017, 02:31:32 PM
echolake1 echolake1 is offline
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Default Re: onan 3 wire to 4 wire transfer switch receptical

Thank You for the " Overheat Neutral added answer. I am actually using 6 Gauge stranded wire for all my hookups. Won't that eliminate wire heat up under normal house currant usage . No garbage disposal, washer/drier usage etc.

---------- Post added at 01:31:32 PM ---------- Previous post was at 01:19:16 PM ----------

PS. to all My service panel has a Total disconnect Other then the service panel breaker to avoid feedback pass the "Main breaker"
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Old 02-22-2017, 02:32:09 PM
TLB01 TLB01 is offline
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Default Re: onan 3 wire to 4 wire transfer switch receptical

This probably counts as a reiteration but it will work...from a trade craft perspective, but if not sanctioned in the NEC, or other local/municipal codes than it won't "legally" work. That is the demographic of money wranglers that really decide code that could give a rat's pink pimpled ass about trade craft. On their end its what denies claims, wins litigation etc. Culpability.

Some may have misunderstood your intentions as far as back feeding goes. If you have a transfer switch and a main service disconnect breaker than you are fine as far as that goes. You have your ass covered. That is what it all about here. CYA.

Those that mentioned additional over current protection are dead on. My example as posted is for a generator that pushes out at most 8 amps. Anything that gets into the danger zone as far as amperage will have long since popped the overload breaker on the gen and killed the engine.

In your case you need a breaker inline between your Gen and the transfer switch. 30 amp breaker on the generator is a good place to start. A GFCI on the power cord going to the transfer switch may not work in your case depending on neutral bonding.

It also never hurts to do a tally of your loads and then you can further refine your breaker sizing. Stuff with surge loads like a fridge or a microwave need to be x2. Plus, decide what you can not run simultaneously. Watts/volts=amps. Tally them up. Make sure you don't go over 30 amps.

Bottom line here is if you are going to break the rules, do your homework. It sounds like people here, or on any other site telling you "No, you are an idiot for even contemplating that" is probably not going to deter you. Its kind of like if you know your kids are of the age that they might be sexual active...do you just tell them not to do the deed and hope they don't defy your authority that (lolz), or provide them with education and contraceptives?
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Old 02-22-2017, 02:36:34 PM
echolake1 echolake1 is offline
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Thumbs up Re: Onan 3 wire to 4 wire Transfer Switch Recepticle

Thank everyone for there helpful comments. It all makes sense. It sounds like to keep everyone alive is to let the approved Techs. to do the hookup.
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Old 02-22-2017, 02:59:14 PM
len k len k is offline
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Default Re: Onan 3 wire to 4 wire Transfer Switch Recepticle

My concern for overheating the shared neutral issue is with house wiring in the walls.
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Old 02-22-2017, 03:24:02 PM
TLB01 TLB01 is offline
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Default Re: Onan 3 wire to 4 wire Transfer Switch Recepticle

Quote:
Originally Posted by len k View Post
My concern for overheating the shared neutral issue is with house wiring in the walls.
Than it sounds like 15amps is all you safely get and that is your breaker size. A fridge, a TV and a couple of lights are all you are going to be able to operate.

Might be best to pull the permit, hire an electrician and spend the money (probably close to a grand should be set aside) or see what can be done to gen for lesser cost. Pay now or pay later. At least legally when you do that (which is the right way) you shift the onus to a licensed pro and the municipal gov't. If something goes wrong after that, it will be them that get sued, not you.
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Old 02-22-2017, 04:14:59 PM
echolake1 echolake1 is offline
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Default Re: onan 3 wire to 4 wire transfer switch receptical

You are very right, so with that being said, being safe then sorry would be the best option. I'll call the legal elec. pro's in for this.. Thank You
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Old 02-22-2017, 05:00:29 PM
len k len k is offline
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Default Re: onan 3 wire to 4 wire transfer switch receptical

Post the model and serial number of the gen. some can be reconfigured to make 120/240 and that solves your shared neutral problem.
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Old 02-22-2017, 05:22:50 PM
LRomero LRomero is offline
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Default Re: onan 3 wire to 4 wire transfer switch receptical

Quote:
Originally Posted by len k View Post
Post the model and serial number of the gen. some can be reconfigured to make 120/240 and that solves your shared neutral problem.
Post 7 shows the model number, but not the serial number. The OP also states in post 7 that the tag references 120/240 volt.
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Old 02-22-2017, 05:51:43 PM
len k len k is offline
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Default Re: onan 3 wire to 4 wire transfer switch receptical

Ahh... missed that little detail.

The 3CR means you can reconfigure the gen to make 120/240. then you can feed 120/240 to the transfer switch. That should solve your shared neutral risk.

Basically your gen has two windings each making 120V . for 120 only they are wired in parelle, for 120/240 they are wired in series.

There should be a box on gen that you can reconfigure the stator wires M1, M2, M3, M4. I think the box is on top. Others know this gen better than I do. Also either in that box or the by the brushes there should be a neutral/ ground bond that you can open if your N/G bond is in the transfer switch.
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Old 02-22-2017, 07:55:02 PM
echolake1 echolake1 is offline
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Default Re: onan 3 wire to 4 wire transfer switch receptical

After all the Great learning answers asked in this batch of threads all I really want to do is get two (2) 120v wires from my Onan 5.0 120v/240 compatable to my 6 breaker transfer switch. mod.# TK65000 Powermate. 20amp max input, 15 amp max output so it says on the side of the transfer switch box It has a 4 prong receptical . Onan BGA Genset 5000kw. can anyone assist in this. Thanks\

Onan 5.0BGA-3CR/16004V SER.#H800519383
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Old 02-22-2017, 09:46:15 PM
Steve Dawkins Steve Dawkins is offline
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Default Re: Onan 3 wire to 4 wire Transfer Switch Recepticle

Is your generator installed in a motor home, trailer, or other application that is only set up for 120 volts power? That will determine whether you have to leave it at 120 volts, or rewire it for 120/240 volts.

Assuming the generator is not installed, and you can change the output voltage, here is what you can do. Follow the existing output wires back into the generator. They are connected to four wires in the generator. These are the output leads from the generator windings. The leads should be labeled M1, M2,M3 and M4. As presently wired, the M1 & M3 leads probably connect to the 120 volt hot wire, and the M2 & M4 leads connect to the neutral wire. If you want to rewire it for 120/240 volts, you will need to get some 10-4 SO cord or 10-4 STO cord. This will be #10 gauge, 4 conductor cord, with either rubber (SO) or plastic (STO) heavy duty jacket. The cord will have a black, red, white and green wire. Connect to the generator as follows:

M1 - Black ( 120 volt hot / Line 1)
M4 - Red (120 volt hot / Line 2)
M2 & M3 - White (Neutral)
Connect the green wire of the cord to the metal housing of the generator's junction box.

(Note to other posters: I am not a gen tech, but have worked with Onan & Cummins generators for several years, in addition to owning them myself. If the above connections are not correct for the OPs genset model, please feel free to chime in and correct me.

The other end of your 10-4 cord will connect to the twist lock connector that mates with the transfer switch. The terminals in the connector will be marked X,W, Y and green. Connect the black and red wires to X and Y. It doesn't really matter which wire goes to X and Y. The neutral goes to the W terminal. That terminal should also be silver in color, whereas X and Y will be brass colored or painted a dark color.

Look at the inlet plug on your transfer switch. It should be marked either 20 or 30 amps. You can buy the mating connectors at any big box hardware store. You will need:

20 amp: NEMA L14-20C connector (20 amps, 120/240 volts, 4 wire)
or
30 amp: NEMA L14-30 connector. (30 amps, 120/240 volts, 4 wire)

After re-assembling the connector, check the connections before plugging it into the transfer switch. When looking at the face of the connector, the ground slot has a small key at one end. The neutral slot is opposite the ground, and is smaller than the ground and hot slots. Check continuity between the ground slot and the generator frame. Then start the generator and check each hot slot to neutral (120 volts) and between the two hot slots. (240 volts)

Is your transfer switch currently installed, or does it need to be installed? Based on the model number you provided, it has been discontined and I didn't find any literature or a manual for it. If it has not been installed, I can tell you how to connect it to your panel. Unless you are really comfortable working in a circuit breaker panel, I strongly recommend you hire an electrician familiar with these transfer switches to do the work, for safety and liability reason as mentioned in previous posts.
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Old 02-22-2017, 10:47:16 PM
echolake1 echolake1 is offline
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Default Re: Onan 3 wire to 4 wire Transfer Switch Recepticle

I am pretty familiar with this Powermate transfer switch. I did find info. on the wiring by checking out the same diagram on the 6 breaker TS. No difference. I opened my TS and saw that breakers 1 through 3 and 4 through 6 Each take a 120v Hot lead red and black, and then grn. and neutral were left. That's why I need two hot leads from the Onan. It is 120/240 5.0 genset bga...
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