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Discussion Starter · #1 ·
I have a customer who wants to be able to tie-in a portable generator into the service. They do not want to spend money on a transfer switch. We're talking about an 800 amp, 480/277 volt service. I was looking at article 702 and wasnt sure about 702.5 exception and from what Im understanding, I can lockout the main breaker and some how tie-in the generator into service. The "only qualified persons service the installation" part is questionable as always, although they will definitely have an EC make connections when the time comes. Another thing in question is the "portable generator", it is a tractor-trailer sized generator that is hitched and transported. This corp. has several locations in this region and can get the generator on site within a few hours. Am I missing something? Any advice would be appreciated, Ill be bidding against others and I know this company will take the cheapest route, so if this can truly be accomplished without the pricey transfer gear, that will surely be a winner.
 

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I have a customer who wants to be able to tie-in a portable generator into the service. They do not want to spend money on a transfer switch. We're talking about an 800 amp, 480/277 volt service. I was looking at article 702 and wasnt sure about 702.5 exception and from what Im understanding, I can lockout the main breaker and some how tie-in the generator into service. The "only qualified persons service the installation" part is questionable as always, although they will definitely have an EC make connections when the time comes. Another thing in question is the "portable generator", it is a tractor-trailer sized generator that is hitched and transported. This corp. has several locations in this region and can get the generator on site within a few hours. Am I missing something? Any advice would be appreciated, Ill be bidding against others and I know this company will take the cheapest route, so if this can truly be accomplished without the pricey transfer gear, that will surely be a winner.
What you are "MISSING" is the fact that you should not be worried about saving the customer money. When that becomes your focus it makes the job of estimating extremely harder to do. Do the job the way you think is correct and don't even consider the shortcuts...they will cost you time and anxiety.
 

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Discussion Starter · #5 ·
What you are "MISSING" is the fact that you should not be worried about saving the customer money. When that becomes your focus it makes the job of estimating extremely harder to do. Do the job the way you think is correct and don't even consider the shortcuts...they will cost you time and anxiety.
Your absolutely right, my first hurdle was knowing whether or not this could be accomplished without transfer equipment. Now is when I have to look at each site and see how/of its possible.
 

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We do this a lot in telephone switching buildings. They have an onsite stanby generator. And they have an inlent can with cam locks for a portable generator. There are two transfer switches one auto for the standby, and one manual for the portable. The manual transfer switch have two breakers feeding one out put . And the breakers are basically not interlocking. They do have a kirk key setup. One breaker is always off and has the kirk key installed.
This is where the qualified personal comes into play....potentiallly it could back feed one source and cause problems if someone turned both breakers to the on position in the manual transfer panel.
 

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For these larger installations, a Kirk key interlock arrangement can be a budget solution. Only requires a breaker that the generator inlet will feed and some hardware from Kirk. (you may have seen Kirk hardware on main tie mains, etc.) It's the commercial equivalent of the interlockkit.com hardware that we sometimes use in resi work.
 
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800 amp?! 480 volts?! Tractor trailer mounted genset delivered to site within hours?! And they WON'T spring for a transfer switch because they're cheap? Now I've heard it all.
 

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Where I work they got permision to do that, they said as long as you can lock it with the key,and have someone quilified to hook it up, and open the breaker, that it would be ok.
I dont like it,;)
 

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800 amp?! 480 volts?! Tractor trailer mounted genset delivered to site within hours?! And they WON'T spring for a transfer switch because they're cheap? Now I've heard it all.
a generator that size requires a mechanical disconnect
you cannot rely on a main breaker as a means of disconnect (all too often contacts can fuse together) or be forgotten
a transfer switch separates the connections with considerable force and clearance and is the required hardware needed.

we all know this but its important that the customer also knows and abibes by it as well
even small portables can back-feed with quite a wallop to any lineman who is unfortunate enough to be on the receiving end of it
:eek:
 

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Discussion Starter · #11 ·
IslandGuy said:
800 amp?! 480 volts?! Tractor trailer mounted genset delivered to site within hours?! And they WON'T spring for a transfer switch because they're cheap? Now I've heard it all.
Yup, you heard right. They even had they're engineers wright out all the specs, which include Kirk key system and WARNING plaques. With this all being new to me, I honestly thought there was no way this is right, but sure enough I couldn't find anything in NEC to say otherwise. We all know a transfer switch is the best solution, however, that's out of the question, and as long as it's compliant, I could care less how it's done. By the way, they did mention in specs something about drilling and bolting to main busses, which has me thinking that it would probably violate something in article 110. If not, I thought of bolting lugs to buss and running wires over to and through a fused disco, ultimately to an appropriate terminal box for tie-in. This sound plausible?
 

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It's done that way a lot, either as a primary generator connection for a facility that doesn't need an automatic standby and only needs a generator very rarely or as a backup to an automatic at a critical site.

Double throw discos and pin and sleeve or on larger apps a kirk key setup and cam lock connection panels. There really isn't a need for a transfer switch, there isn't anything to transfer till the genny gets there and you hook it up anyway.
 

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There's a few trapped key system manufactures. Kirk is the biggy though, I think kirk is the last name of one of the inventors. The other is Castrell or Castell or something like that I think.
 

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We do this a lot in telephone switching buildings. They have an onsite stanby generator. And they have an inlent can with cam locks for a portable generator. There are two transfer switches one auto for the standby, and one manual for the portable. The manual transfer switch have two breakers feeding one out put . And the breakers are basically not interlocking. They do have a kirk key setup. One breaker is always off and has the kirk key installed.
This is where the qualified personal comes into play....potentiallly it could back feed one source and cause problems if someone turned both breakers to the on position in the manual transfer panel.

Not to familiar with kirk. Is page 5 an good example? Just wondering how these are applied as ATS.

http://www.kirkkey.com/websiteimages/KKIC_2009_Brochure.pdf
 

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That's the one.
My impression is because in theory only a qualified individual will be servicing these sites. This is allowable.
Because if someone were so inclined the lock could simply be removed and either the generator, or utility could be back fed.
The setups I've seen are simply a rod through the breaker lock hole. And you unlock one and install the same lock on the other.
Maybe at&t is different than other sites, but this is fairly common.
 

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Any members from Canada( Nova Scotia) out there who can help me find work?"
please do not multi post the same message like this it is classed as spamming and can get you banned
 
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