Taps Feeding Taps?

G

gonzoleroy

Member
Location
United States
Hello all. I am not well-versed in taps. I have a battery charger vendor who has put together a scheme (photo below) for distributing power to a rack full of forklift-style battery chargers. The portion of the drawing above the horizontal line is existing infrastructure, while the lower portion is what they propose to add.

My initial thoughts are:
  1. Existing infrastructure, now that I examine it closely, is in violation of 240.21(B) (3). The length of #1 AWG from the I-Line panel to the first splitter is over 25 ft. Also 240.21(B) (4) cannot apply since this is not a manufacturing building. Furthermore, there are cases of horizontal conductor length greater than 25 ft, and it also penetrates a ceiling. (There are (6) of these circuits in total).
  2. The proposal by the battery charger vendor would further introduce taps feeding taps, which I understand is not allowable (though not specifically spelled out in the NEC).
I plan to make this entire installation code correct, not to add further violations on top of an already non-compliant set of circuits.

Am I looking at this correctly in terms of the NEC? Please share any thoughts.

Charger Plan.png
 
petersonra

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
gonzoleroy said:
The distribution blocks in each splitter made me think of taps. Are they not taps due to having separate OCPD on each of the 125, 30, and 10-amp sections?
Click to expand...
Yes. The taps start at the splitter blocks and go to the circuit breaker terminals. The wires coming into the splitter blocks are not tap conductors because they are properly protected by upstream ocpd.

If I were making these I might not have used a splitter block at all. There are bus bars made for these miniature circuit breakers.
 
H

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
Wouldn’t this fall under manufacturers pre assembled device?
 
petersonra

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
It looks to me like this is just some circuit breakers and receptacles to plug chargers into.

You might be better off just getting a 3 phase panelboard and just installing receptacles where you need them.

I don't see how it would be code legal to plug the four circuit things into the 30 amp receptacles
 
G

gonzoleroy

Member
Location
United States
petersonra said:
It looks to me like this is just some circuit breakers and receptacles to plug chargers into.

You might be better off just getting a 3 phase panelboard and just installing receptacles where you need them.

I don't see how it would be code legal to plug the four circuit things into the 30 amp receptacles
Click to expand...
10kA is the rating for the four-output, 10-amp "splitters". These splitters are not UL listed. There is a tag stating "FIELD EVALUATED EQUIPMENT This equipment complies with the specific ANSI/UL standard(s) for safety noted in the Field Evaluation report, limited to electrical fire and shock hazards."
I do not have specs for the six-output, 30-amp model from the drawing.

I would love to put panelboards in place of these splitters. The trouble comes with the cost, both financially and with downtime, to make that happen. Yet I have to ensure code compliance, so this is a battle I will have to take up.

Also I agree the 4 x 10-amp splitters being fed from 30-amp receptacles is a problem, and it kind of surprises me that the vendor "engineers" produced such an idea.
 
petersonra

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I think if you ran MC from the 30 Amp boxes to the ten Amp boxes it would probably be code legal IF the available short circuit current was less than 10 kA at the end of the #1 cable. You will have to know that anyway to label the homemade panelboards.
 
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