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[Curt Sorensen]

Hi,
I didn't want to hijack the thread about single phase tie-ing into 3-phase with this question. We may be faced with sharing a 400 amp panel with another, likely 100 amp, distro at an upcoming event. Our truck is set up for 200 amp service. I assume from the other thread that both systems should provide feeder cable rated for 400a service or use the short-run method [don't know a better term] to a main breaker before running to each of the systems. If so, I can see how this might not be done to code all that often.

Sharing such as this would be a first for us, so feel free to make any comments on sharing a panel [using cam-lock tees I assume]. Note I am not the person responsible, but I've really benefitted from this forum, and if I can pass along useful information and aid in safe operation that's my only goal.

Thanks,

[TJ (Tom) Cornish]

Hi,
I didn't want to hijack the thread about single phase tie-ing into 3-phase with this question. We may be faced with sharing a 400 amp panel with another, likely 100 amp, distro at an upcoming event. Our truck is set up for 200 amp service. I assume from the other thread that both systems should provide feeder cable rated for 400a service or use the short-run method [don't know a better term] to a main breaker before running to each of the systems. If so, I can see how this might not be done to code all that often.

Sharing such as this would be a first for us, so feel free to make any comments on sharing a panel [using cam-lock tees I assume]. Note I am not the person responsible, but I've really benefitted from this forum, and if I can pass along useful information and aid in safe operation that's my only goal.

Thanks,

The usual way to do this is to use feeder cable rated for the full 400A for both distros, and either use the distro passthrough cams if equipped (which are almost always rated for 400A), or cam T connectors.  The main breaker on the distros will then protect the internal busses of the distros at the appropriate 100A/200A rating.

[Mark Cadwallader]

I have also seen tie-in locations that allow for multiple sets of tails to be tied in. As always, only a "qualified person" (typically a licensed electrician) performs the tie in to the bus bars in the disconnect box.  That avoids the use of tee connectors, which not everybody carries.

[Ray Aberle]

That avoids the use of tee connectors, which not everybody carries.

... but everyone should. I mean, the cost of a set of tapping tees is-- what, under $200? And add some turn-arounds, you're barely at $300. A small price to pay to be able to always make things work, in my mind. I had tapping tees before I even had more then one distro, just in case I was faced with a situation where I needed to access someone else's cam feeds.

Curt, I'd really suggest carrying your own cam tees so you are always prepared.

-Ray

[John Daniluk (JD)]

If you are sharing power feeds, keep track of the total load.  200a +200a =400a  may be a tripped 400a breaker (heat).