Tapping a Discontinued Switchboard

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Tainted

Tainted

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New York
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Engineer (PE)
Long story short, I want to get power from a 600A 120/208V 3 phase switchboard and the switchboard is full. The most cost effective way to get power would be to do a tap in the bus but the switchboard is discontinued and I am concerned about doing any modifications to it because I can't find any information about it. When I did the survey, there was no electrician there to open up the switchboard so that I can see what can be done. The switchboard is by "Electric Switchboard Co. Inc." Does anyone have any information on this switchboard? What are my options?
 
Tainted said:
Long story short, I want to get power from a 600A 120/208V 3 phase switchboard and the switchboard is full. The most cost effective way to get power would be to do a tap in the bus but the switchboard is discontinued and I am concerned about doing any modifications to it because I can't find any information about it. When I did the survey, there was no electrician there to open up the switchboard so that I can see what can be done. The switchboard is by "Electric Switchboard Co. Inc." Does anyone have any information on this switchboard? What are my options?
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Not enough information. What are we talking about here? Line side or bus side tap? MLO or Main Breaker involved? Is the tap extending outside of the switchboard or staying within it? What is the calculated load wrt the continuous bus rating?

Doing a bus tap will likely violate the listing of the switchboard and transfer any liability onto you. It could be done (assuming its properly engineered), but you should probably do a UL field inspection and get confirmation from the AHJ that this would even get approved.
 
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Xptpcrewx said:
Not enough information. What are we talking about here? Line side or bus side tap? MLO or Main Breaker involved? Is the tap extending outside of the switchboard or staying within it? What is the calculated load wrt the continuous bus rating?

Doing a bus tap will likely violate the listing of the switchboard and transfer any liability onto you. It could be done (assuming its properly engineered), but you should probably do a UL field inspection and get confirmation from the AHJ that this would even get approved.
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MLO, feed goes something like this:
Service end box -> 2 sets of conduit -> main 600A switch -> wireway-> CT cabinet -> wireway -> MLO 600A switchboard
 
It's probably going to depend on what your AHJ thinks. I have found that typically the bus bar bolt patterns conform to NEMA standard and in the past I have had AHJ's agreeable to me bolting on lugs at these joints without requiring a field evaluation.
 
electrofelon said:
It's probably going to depend on what your AHJ thinks. I have found that typically the bus bar bolt patterns conform to NEMA standard and in the past I have had AHJ's agreeable to me bolting on lugs at these joints without requiring a field evaluation.
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If the holes are already there, I can't see the inspector objecting
 
petersonra said:
If the holes are already there, I can't see the inspector objecting
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Well it kinda depends where those holes are and if you have the clearance you need with the bus arrangement. You also need the contact area (most likely those existing holes are oblong). Its pretty simple, if the holes weren’t designed to have lugs, then you can’t do it without voiding UL certification.

I agree that a line side tap at the incoming conductors might be easier because it’s not really a bus tap. Getting the lugs connected properly is only part of the issue.
 
Tainted said:
MLO, feed goes something like this:
Service end box -> 2 sets of conduit -> main 600A switch -> wireway-> CT cabinet -> wireway -> MLO 600A switchboard
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Is there a reason you can’t do a tap at any of the above equipment (other than the switchboard)?
 
Tainted said:
I don't know what's inside there that would allow me to do the tap. I wasn't able to open up the equipment.
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Assuming you have the volume you need, I would think you could make a tap in the wireway.
 
Xptpcrewx said:
Assuming you have the volume you need, I would think you could make a tap in the wireway.
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What kind of tapping device do contractors use? How much space does it usually take? How long does it take? Power needs to shut down for tap
 
electrofelon said:
Are there any free lugs in the CT cab?
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Like I said..., there was no electrician to open up anything when I did the survey. Anyway, I did find a solution but it's gonna be costly. There is a single unit 200A vacu break switch in the switchboard, I will replace it with a double unit 200A vacu break switch so this will give me 1 spare switch.
 
I run into this quite a bit and rarely
Support a game plan for tapping the bus in any circumstance. Question for those in The field . How common is it to have the bus bars provided with the factory templates where is ok to drill/tap . I’ve heard it mentioned a lot and if that were the case it would be much easier to get On board but just curious how common it is to have those
 
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