Bonding jumper size

Status
Not open for further replies.
B

Bill Turax

Member
Location
MD
I have a 2000A service, 120/208V

plans call for 6 sets of (4) 600 AL to the CT cab. the CT needs to be top fed. So my 6 sets of 4" PVC will come from underground, up a strut rack and into a trough that connects to the top of the CT cab. I will have (6) 3" rigid nipples between the trough and the top of the CT cab.

my question is the size of the bond jumper for the 3" bond bushings in the trough. my understanding is that the size of the bonding jumper needs to be 12.5% of the combined size of the ungrounded conductors per phase. so in this case the service is 2000 amps. if the feeds were copper than I would have 6 sets of 400, this would be a total of 2,400 kcmil. so the bonding jumper needs to be 300 kcmil (2400*.125).

my issue is that I cannot find a bond bushing that will accept 300. I also cannot find any lay-in lugs that will accept 300.

since the product is not available, this makes me believe that I must be doing something wrong or overlooking something that is causing me to come up with the incorrect wire size.
 
What Dennis said above. Here's a link to the part with the correct lug. You can buy them no need to replace. Of-course if you can find it to buy, make it. Note the link is for 4" RMC

www.eaton.com

Eaton Crouse-Hinds series GLL grounding bushing - GLL10 DC Overview | Eaton

GLL10 DC - Eaton Crouse-Hinds series GLL grounding bushing, Rigid/IMC, Aluminum lug, #3/0-6 AWG, Zinc die cast, 150°C, Threaded, 4"
www.eaton.com www.eaton.com

Also where are you getting 12.5%? Sizing I thought was based on the table 250.102(C)(1) or if load side 250.122? Am I mistaken?
 
If you use an individual jumper for each raceway each jumper can be 1/0 CU or 3/0 AL. See 250.102(C)(2). This is different than jumpers on the load side of an OCPD where the jumper would have to be for the sum of all ungrounded conductors.
 
Status
Not open for further replies.
Top