Connecting 2 generators to a transfer switch

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Old 07-30-10, 07:33 AM
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Connecting 2 generators to a transfer switch

I'm having a problem connecting my two Honda EU2000i generators to a Reliance Controls 3006HDK transfer switch. The generators are paralleled with a Reliance Controls HPK2001 Parallel Power kit and output to a 3-prong 30 amp RV outlet (one hot, one neutral and a ground). The 3006HDK trans switch has an 4-prong L14-30 power inlet (two hots, a neutral and a ground). The two hot wires power two banks of three breakers (one 20A & two 15A), each bank fed from its own hot lead.

So howinhell do I connect these two? I'm pretty sure it's a bad idea to connect the single hot lead from the 30 amp RV outlet to the two hots of the trans switch inlet (neutral wire overload) but how else can this be done? I'm thinking that my only options are to replace the trans switch with one that requires only one hot lead or to connect the 30A RV outlet hot wire to one of the L14-30 hot leads and use only 3 of the 6 available circuits at the transfer switch. This would work, but I'd obviously rather have all 6 circuits available.

Any ideas?



Thanx - Rick
 
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Old 07-30-10, 09:03 AM
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Here's the reply from Reliance Controls:

>>>Thank you for choosing our products.

The 3006HDK is configured for a 30 amp 125/250 volt configuration, the NEMA " L14-30 ".
An L14-30 output has 2 x hot legs each with 120 volts (120 positive, 120 negative, the difference is 240).

Your generators produce 120 volts only, on a single hot leg. So through the parallel kit, which has a NEMA outlet " L5-30 ", you are getting 120 volts on a single hot.
There are no adapters I'm aware of that will split one hot leg into 2 hot legs. Usually this is something that must be custom made.

The only option in your current situation is purchase an L5-30 male plug that fits into the parallel kit, if you don't already have one. Then you would have to make your own cord so that one end has the L5-30 plug for the parallel kit, and the other end (female) has the L14-30 that will fit into the PB30 power inlet box. When putting a 3 wire plug onto a 4 wire cord, there will be the 1 hot leg leftover. This is the important part, as in the 4 wire cord, 1 hot lead will feed half of the transfer switch (A, B, and C) and the other hot lead feeds D, E and F. So the single hot lead in the L5-30 plug must somehow be connected to both of the hot leads in the 4 wire cord.

The only other option, is to acquire a 120 volt ONLY transfer switch, meaning the transfer switch has only 1 hot lead, like your generators. We do sell model 30216A1 to Honda, so you can purchase that model from a Honda Dealer if you want to go that route - where everything will be 120 volts only. As of now, your generators are 120 volt only, everything else is 120/240 volts, so there needs to be a modification for it to work properly. If you have any other questions please let me know!<<<

So Reliance is saying that I can put the single 120v output from the generator on both of the inputs to the trans switch. This sounds like getting something for nothing so I'm looking to you gurus for confirmation.

The paralleled gennys make 4000 watts at peak power (3200 watts rated output) which comes out to 33.3 amps on the single hot output. Wiring between the remote power inlet box and the trans switch is 100' of 10/3 w/ground so it looks like their suggestion makes sense.

Anyone disagree?
 
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Old 07-30-10, 09:14 AM
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Originally Posted by roach711 View Post
I'm pretty sure it's a bad idea to connect the single hot lead from the 30 amp RV outlet to the two hots of the trans switch inlet
Nope, that's the correct way with 120V generators. There should be no risk of overload because the generators each have breakers and the parallel power kit has a breaker. If you have any double-pole breakers (240V) in the transfer switch, they will not work but all of the single pole breakers will be fine with this.

I would replace the 14-30 inlet at the transfer switch with a 5-30 inlet (common RV part) so there's no confusion about which cords to use. Make the connection of the hots inside the transfer switch and not inside the cord. This makes it impossible for someone to accidentally plug it into a real 240V source and short it out. I also like to print a label on the transfer switch that says something like "WIRED FOR 120V 30A SOURCE ONLY".

my only options are to replace the trans switch with one that requires only one hot lead or to connect the 30A RV outlet hot wire to one of the L14-30 hot leads and use only 3 of the 6 available circuits at the transfer switch.
Either of these is also okay.
 
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Old 07-30-10, 07:15 PM
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I'm a little confused about why you only have a single hot coming out of the parallel kit. Isn't the whole point of a parallel kit to sync the generators into a split phase for exactly this?
 
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Old 07-31-10, 07:54 AM
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Originally Posted by JerseyMatt View Post
I'm a little confused about why you only have a single hot coming out of the parallel kit. Isn't the whole point of a parallel kit to sync the generators into a split phase for exactly this?
Not in this case. These are two small generators, and the Reliance Controls HPK2001 is a small simple paralleling kit. Basically just a set of Y connections with proper fittings. With a hookup like this the generators are forced to be in phase, any deviation means one generator fighting each other. So the phase ends up locked.

If you want to maintain opposite phase, with a single ungrounded conductor coming off the generator, you'd need to have electronics in the inverters hooked together with a data cable. That's money and complexity which would have to be built into the generators by Honda.
 
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Old 07-31-10, 03:57 PM
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Hmm.. I doubt it would need anything else built into the generators... The synch connections are already there. That's how the parallel kits synch the wave. Wouldn't you just have to put a circuit in between them that flips one of them 180 degrees (as opposed to synching them)? Then tie the neutrals together and use one hot as L1 and the other as L2?
 
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Old 08-01-10, 06:27 PM
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Thanx for the help and confirmation guys.

I ended up building a patch cord with an RV 30amp plug on one end and an L14-30 receptacle on the other. The two hot wires are soldered together near the L5-30 plug. Works fine and I got WAY more familliar with generator electronics. lol
 
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