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Field Mods to Switchgear #46358 12/19/04 11:35 AM
Joined: Apr 2001
Posts: 507
golf junkie Offline OP
I recently bid on a project for a 4 story addition to a bank building.

The switchgear was a 30 year old Federal Pacific 1200A panel with two 600A fused switches. The engineer had specified a new 1200A GFI main breaker to be installed in the old switchboard.

The only way to accomplish this would be to fabricate the mounting system and the sheetmetal required to enclose the front of the switchboard. Are these types of mods normally done?? Doesn't field modification violate the equipment listing?

Would you allow this in your jurisdiction if it was done under engineering directive?

[This message has been edited by golf junkie (edited 12-19-2004).]

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Re: Field Mods to Switchgear #46359 12/19/04 02:53 PM
Joined: Aug 2004
Posts: 42
HighPotter Offline
Did the engineer specify a manufacturer of the main breaker?

Will said manufacturer provide " field techs" for the installation?

Has there been any plan review by the local ajh

Re: Field Mods to Switchgear #46360 12/19/04 04:24 PM
Joined: May 2001
Posts: 376
frank Offline
We had the same service entrance at a hospital.We had to shut it down so the poco could crawl in there and install a pulse meter.Although the FPE scare didn't include it management called in an outside contractor to open the main for third party liability and parts would not get here for at least two weeks.Our guys had to start the emergency generators in load test to let the automatic transfer switch shed the load before the mains were opened.Anyway we've had trouble before and at one point ended up building a breaker box that sat in front of the panel on the floor for a month until a new one was made maybe they still can?.It was in fact because of inspection that we had to do this they would only allow listed replacement parts with no modification.Otherwise they said it would have it be checked out by their special permission devision at a cost of $200.An inspector shows up and tells you what to do.They don't want you to cut into the cabent door ever.
Like HighPotter said get the manufacture involved or make the engineer get them and find the proper breaker then call inspection with all information on the parts.
Honestly on something like this i would drop it back in the engineers lap.Isn't device selection and selective coordination his problem anyway? Around here the engineer anwers to the inspector.

[This message has been edited by frank (edited 12-19-2004).]

Re: Field Mods to Switchgear #46361 12/19/04 08:54 PM
Joined: Feb 2003
Posts: 169
russ m Offline
I'd look for a company that makes switch gear and panels. they will send someone out to check the equipment, and will provide you with componants that fit right in, even if they have to manufacture it.

Re: Field Mods to Switchgear #46362 12/19/04 08:58 PM
Joined: Apr 2002
Posts: 2,527
Bjarney Offline
There is an national-consensus standard that deals with switchgear modifications, but if it has not been referenced by engineering concerns or unfamiliar to the AHJ, there’s not much point using it, other than to relieve some liability of the organization performing the work. ANSI/IEEE Std C37.59-2002 …Requirements for Conversion of Power Switchgear Equipment [An earlier version is described at The 2002 edition is cataloged at]

Re: Field Mods to Switchgear #46363 12/20/04 06:20 PM
Joined: Apr 2001
Posts: 507
golf junkie Offline OP
We didn't win the bid so it's a moot point, probably a good thing.

It was an unusual situation and I was wondering what others have done.

In Nebraska the AHJ does not do plan review for electrical.

The engineer answers to no one except the architect who hired him. All code compliance issues fall back on the contractor. In fact the engineer and architect will put in their contract that they are not responsible for errors and omissions.....I wish I could work that way.

The gear was bid by both Sq.D and Siemens. Sq.D provided a field service tech to install the main. Siemens provided just a breaker. There was about a $30k difference.

Re: Field Mods to Switchgear #46364 12/20/04 09:58 PM
Joined: Sep 2004
Posts: 167
sandsnow Offline
Field modifications do not neccessarily violate a UL listing. UL likes to use terms like the significance of the listing MAY have been compromised. Only examination by UL can determine that. And then UL will say the equipment is no longer eligible to bear the UL mark, and they will take their sticker back.

An AHJ can approve a field modification or ask for a field inspection from UL. If the manufacturer no longer supports the product, then I don't know what would happen.

It seems here the big question to me would be is the withstand rating or fault current bracing when it's all bolted back together.

We've had old existing switchboards and new sections made by another manufacturer, and there and have accepted almost all without field eval's.

Larry LeVoir
City of Irvine, CA


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