generator/transfer switch question

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220/221

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Educate me generator guys.


120/208 3 phase commercial building.



A business has some sensitive equipment (several circuits) that can't be off for more than an hour or so. They want to be able to manually plug in a portable generator to stay on line in case of an extended outage (There is no close place to put a permanent generator).



I am thinking of supplying the equipment from a sub panel, supplied thru a transfer switch, via (1) house power and (2) a plug to accept the portable generator power.


QUESTION: I am assuming that when installing a manual transfer switch you have to break the grounded conductor along with the ungrounded conductors......right?


Related question. Can I leave a male cord cap/pigtail off the transfer switch to plug into the generator? The cord cap could never be hot (as it is SUPPLYING power) but it just LOOKS wrong to have a male cap coming from a switch like that.



We don't have any real weather issues here so I haven't installed anything like this since the Y2K scare :) :)
 
220/221 said:
Educate me generator guys.
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You might consider using an automatic transfer switch, even if you're connecting a larger portable generator. I did this for a couple "backup" 9-1-1 call centers. The county has a generator available for use where ever.

The pin and sleeve inlet that you would use has the capability of having "pilot duty" pins in it, in addition to the current carrying pins. These two pins are the start contact for the portable generator. This is the way I did it.
 
I thought that the low tech method would work better in this case.

The equipment keeps water tanks at a certain temp to grow coral......yes coral. An alarm company will monitor the status and notify him in case of trouble.


The electrical system is pretty reliable here. RARELY is power out for more than an hour. The business owner thought it would be no problem to go there, start the generator and throw the switch.
 
BTW, you don't have to transfer the neutral in this case unless you want to. You really don't want to, trust me. Just makes the job harder and messier.

Beware of Honda portable generators in this application.
 
Marc's idea will work fine with this setup.

But however i just like to remind you to tell the owner if he used the portable [ trailerable ] generator just make sure he get correct voltage other wise it will do funky thing if the owner switch the generator output voltage to delta system instead of wye connection [ most trailerable generators do have multivoltage/ phase connection so watch out with this one ]

Merci, Marc
 
frenchelectrican said:
Marc .,,

If you dont mind but can you tell me the reason with Honda generator with this one ?? [ i know majorty of Honda generators are single phase unit]

Merci
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I guessed that he might just be backing up a few single phase circuits.

Honda portable generators, among a couple others I suppose, have a GFCI type main breaker. It will trip if you do a solid neutral. You need to cut a jumper internally, which effectively makes the generator unsuitable for use as a stand-alone generator for other uses. They're just a pain, is all. Not unusable, but they can be work you didn't bargain on.


7. Why does the generator GFCI trip on some generators when used with a transfer switch?
Download Honda Generator Service Bulletin
NOTE: AFFECTED MODELS ONLY INCLUDE: HONDA Models EB3500XK1, EB5000XK1, EB6500SX, EB12DAG, Arctic Cat Model 1999 AC7500GD2EB and some models from Briggs and Stratton.
The Honda EB (Industrial/Commercial) series generators listed above have their neutral wire bonded to the ground wire to pass OSHA inspection on job sites. Since home and building main load centers also have the neutral bonded to ground, a loop is created, comprised of the neutral wire and the ground wire. A small amount of current is induced in this loop by the running generator. Since the neutral wire passes through the ground fault sensor, the GFCI senses this induced current and trips the main circuit breaker in the generator.

When using these EB series generators to power a house or building through a transfer switch, the neutral bond wire on the generator must be removed, preferably by the Honda or Arctic Cat dealer or a qualified electrician. NOTE: After this action, the generator will no longer pass OSHA inspection on job sites. Contact a Honda or Arctic Cat dealer to remove the neutral bond. Ask the Honda dealer to refer to the Honda Service Bulletin #20 for instructions on removing the neutral bond.
 
My only question is how are you going to work some plastic bushings into this installation?
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Oh I'll find a way. I will probably tape/mark some #6 wire too while I'm at it.


Is he going to be able to find a 3 phase, 50-60 amp portable generator?

How big will it be? I was hoping he could mount it on a dolly of some sort and wheel it 20' outside.
 
220/221 said:
OIs he going to be able to find a 3 phase, 50-60 amp portable generator?

How big will it be? I was hoping he could mount it on a dolly of some sort and wheel it 20' outside.
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They certainly exist, but they're a little salty. Most of them are built to military specs when you get into man-portable 3 phase units. Robin (Subaru) is one manufacturer that comes to mind right away for such units. A 50-60 amp unit is not at all man portable by any means. That's a dog-gone truck engine to power a unit that size. For that many amps, you're talking about a trailerable unit. Maybe he has a garden tractor to move it around at that location?

EDIT:

http://www.robinamerica.com/generators/detail.lasso?mdl=RGV13100T
 
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A 3 phase generator that size is going to be a big pricey unit. I
would guess on a tandem trailer with a belly diesel tank 8' long,3' wide & 5' tall-Ed
 
frenchelectrican said:
that is multivotlage/phase unit not very noisy at all.
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How would you know? :grin:

Just teasing you, buddy!

I've never heard of MQ Power. I guess it depends on what they sell in your area. In my neck of the woods, if you need a trailerable unit PDQ, you're getting a CAT.
 
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http://www.robinamerica.com/generators/detail.lasso?mdl=RGV13100T


Thanks for the link. That unit looks managable and looks like it's good for 30 something amps.

I will be at the jobsite tomorrow and will see first hand what needs to be powered.

I am still confused as why the neutral would not have to be disconnected at the transfer switch. It seems as though power could somehow leak back thru the utility system. That's GOTTA sound stupid but, hey...I never claimed to be all that smart.

You guys know what your're talking about so I don't really NEED to understand, just to trust.;)



Holy crap! The difference in size between the 30 amp http://www.robinamerica.com/generators/detail.lasso?mdl=RGV13100T and the 55 amp http://www.mqpower.com/pages-products/whisperwatt/three-phase/DCA-25SSIU.html generator is HUGE!
 
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LOL Marc :grin:

but really MQ is pretty common used in rental fleet and they can take alot of abuse.

but there are quite few manufacter make this size some are interchangeble all they do is swap the namebrand i know MQ and PQD and few others i just can't named them yet because i havent verify it fully but some are from same manufacter

i just have one generator not too long ago ran into it called stuido [sp] generator unit that thing is super quiet somehow little more quiet than car engine it pretty easy to spot it due superoversized housing .

Merci, Marc
 
A couple of years ago I had to bring in a generator to keep a business up while we were changing out the service in comercial duplex.

The city inspector fined me for not getting a separate permit for the temp generator.

Who knew??
 
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