Main lug jumpers

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Jhaney

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Location
owensboro, ky
I'm trying to determine is this setup is legal or not unfortunatly my 2005nec is unreadable and my 2008nec is due any day.
The place I'm working is installing 100A, 120v main lug panels and tying the main lugs (jumper from lug to lug) together. They are bringing main power in on breakers 2 and 4, 2 is a 70A breaker from the battery charger and 4 is a 70A breaker from the backup batteries (by the way this is a DC installation). All the while the zero voltage is coming from the neutral bus bar. Is this legal?
I will attach pictures as soon as I figure out how to.
 
How are you jumping the lugs? They may not be rated for 2 wires. (You wouldn't be able to take a conductor to lug 1, and a jumper from lug 1 to lug 2.)

I can't really comment on the rest.
 
the pictures are on my work computer and I can't upload them
the main lugs are jumpered together and the main power is coming in on breakers 2 and 4
This is done by a "technician" in another state and I'm supposed to be approving this practice or coming up with a better solution. Unfortunatly my assistant had issues with his coke and i can't read my 2005nec and my 2008nec isn't here yet
 
kentonbox3.jpg
 
Comments, in no particular order:

Where did you find 70a 1p breakers? Or are they really a 2p with the handle tie removed? (remember, if it's the latter, they'll still both trip in unison if one does.)

Those breakers, used as supply, require a hold-down kit.

Otherwise, I see no issue, as long as the equipment is rated for use on DC.
 
408.36(D) - the back-fed breakers need to be secured.

It looks like the "neutral" lug has 2 conductors, and I don't think that lug is rated for it.
 
LarryFine said:
Comments, in no particular order:

Where did you find 70a 1p breakers? Or are they really a 2p with the handle tie removed? (remember, if it's the latter, they'll still both trip in unison if one does.)

Those breakers, used as supply, require a hold-down kit.

Otherwise, I see no issue, as long as the equipment is rated for use on DC.
Click to expand...

Square D QO breakers are rated for 48VDC, though I don't know if that is for 2 pole only.
 
My job is approving or disproving some of their as built designs. I don't know where the breakers came (all I got was pictures and a rough sketch, this job site is in another state) from I did research on square D's website and determined the breakers are approved for up to 48V DC. But my main concerns with this installation is the main lug jumper and the 2 neutral conductors. They require all installations to be NEC compliant.
So needless to say I spend 8 hours a day 5 days a week back checking jobs. So glad I found this forum :wink:
 
Besides two conductors in a lug rated for one, article 240.8 does not allow parallel breakers unless factory assembled.
 
what kind of wire is that? it looks to be finely stranded like welding cable or something that the lugs may not be suitable for.
 
wireguru,

I'm not sure what kind of wire it is thats on my list of questions for this job. Once I put my list together and submit it, it may take months for me to get the required information back.
 
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