Daisy Chain equipment grounding conductor

[Hugh W]

I need help on a grounding application? I havea 200A 480V 3-phase feeder 3/0 THHN feeding eight battery chargers with 30Adisconnects at each charger. I plan on using a 3-pole distribution blockto feed each charger with #10 THHN and one grounding block to distribute the #4THHN grounding conductor with #10 THHN daisy chained to each charger. CanI daisy chain the #10 to each charger or do I need to pull eight #10?s to eachdisconnect?

 

[augie47]

IMO, you could not daisy chain.
The allowance to use #10 on the taps is based on the equipment ground not having to be larger than the circuit conductor. If you were to daisy chain you would actually be grounding multiple #10 taps.

side note: how long are your taps ?

 

[Dennis Alwon]

As long as the equipment grounding conductor is appropriately sized for the 200 amp--- #6 according to 250.122 then that is all you need. You can then split to #10 for the batteries from the one #4 (in your case) equipment grounding conductor.

 

[Dennis Alwon]

BTW- welcome to the forum-- Looks like you are right next door to me in NC

 

[kwired]

Dennis the question in post 1 is a duplicate of another thread.

 

[Hugh W]

The taps will be 20' (shortest) to 60' (longest) from grounding block where #4 terminates.

 

[Hugh W]

Thanks Dennis.

 

[Hugh W]

Can I take one #10 to first disconnect and then to 2nd.... 8th?

 

[Dennis Alwon]

Can I take one #10 to first disconnect and then to 2nd.... 8th?

The equipment grounding conductor must run with the circuit conductors per 300.3(B). Not sure how you are doing this daisy chain.

 

[Hugh W]

In series generating from grounding bar to last disconnect.

 

[Joe Villani]

The taps will be 20' (shortest) to 60' (longest) from grounding block where #4 terminates.

You need to review the tap rules in article 240.

You have some code issues here.

 

[Dennis Alwon]

It seems there is confusion on tap rules but the op seems to be talking about the equipment grounding conductor. Assuming the taps are compliant the equipment grounding conductor may be shared but I am still not clear on how this is done. The term daisy chain has me wondering if the equipment grounding conductor is being run with the circuit conductors or not.

You have a 200 amp 3 phase feeder but is it feeding a panel or not-- if not then tap rules do come into play.

 

[Joe Villani]

In the OP he mentioned a distribution block so I assumed taps.

Based on the length of the tap conductor, the equipment grounding conductor size will change.

 

[augie47]

Hugh W:
The reason I asked the tap length was I feared what others have pointed out.
You do need to review the 240.21 tap rules. Your #10 tap will not qualify in most cases, and taps over 25 ft are very restricted.

Dennis: What I pictured was his running phase conductors plus an equipment ground to the first disconnect and then routing the equipment ground back thru that conduit to a 2nd, 3rd & 4th. If that is the plan, I feel it's a violation.

 

[Hugh W]

Thanks for your help. I will keep my tap lengths less than 10' and the grounds as well.

 

[Hugh W]

Another question about this application. I will keep my tap conductors less than 10' and use #10's to feed each disconnect from distribution block, also I will use a grounding block to distribute the grounds to each 30A disconnect, so do I need to use #8 ground wires to each disconnect per Table 250.66?

 

[augie47]

FROM 250.122:
[FONT=&quot] "........equipment grounding conductors of the wire type shall not be smaller than shown in Table 250.122, but in no case shall they be required to be larger than the circuit conductors supplying the equipment. [/FONT] "

 

[sandsnow]

Based on the length of the tap conductor, the equipment grounding conductor size will change.

Please clarify why the EGC would get bigger