Busway cable drop length - secured & supported over 6'

[housemoney]

Our flexible cord drop is 12' from upper busway tap box to the equipment. AHJ is telling us this violates 368.56B (not exceed 6'). What are some ways around this? I proposed securing & supporting the cable on the lower busway with a cable loop- red line (which is 6' above the equipment), but the AHJ wouldn't provide any feedback..

 

[DBill64]

Our flexible cord drop is 12' from upper busway tap box to the equipment. AHJ is telling us this violates 368.56B (not exceed 6'). What are some ways around this? I proposed securing & supporting the cable on the lower busway with a cable loop- red line (which is 6' above the equipment), but the AHJ wouldn't provide any feedback..

368.56(B)(2):

• (2) The length of the cord or cable from a busway plug-in device to a suitable tension take-up support device shall not exceed 1.8 m (6 ft).

The section says that the you cannot exceed 6' between the "plug-in device" (where it goes from the bus to cable) and the suitable tension take-up device. So you could have the tension take-up device installed & supporting the cable 6' (or less) from where the cable-to-bus connection is, then have the cable drop down to the server rack as there is no a length issue AFTER the tension take-up device. After the tension take-up device the cable is then treated as a vertical riser. according to (3):

• (3) The cord and cable shall be installed as a vertical riser from the tension take-up support device to the equipment served.

I do not believe just looping the cable around that lower bussing would be considered a "suitable tension take-up support device", as doing so would make the bussing itself the "support device". What you would want to use is a "bus drop-cable support grip". Hubbell makes some pretty good ones. Grainger sells them for like $33. Just make sure to get one that has a cable diameter range suitable for the cable you're using.

 

[DBill64]

Also there is an exception to this rule:

Exception to (B)(2):
In industrial establishments only, where the conditions of maintenance and supervision ensure that only qualified persons service the installation, lengths exceeding 1.8 m (6 ft) shall be permitted between the busway plug-in device and the tension take-up support device where the cord or cable is supported at intervals not exceeding 2.5 m (8 ft).

So if this is a server rack in an industrial facility, then you have an extra 2 foot allowance as long as you support it in intervals not exceeding 8 feet.