How do I ground this?

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
The PV contractor I work with is installing a system that has a Fortress Evolt 18.5 battery which is the size of a dishwasher and has been installed under the inverter inside a garage. It comes with a prewired plug and cord that connects it to the inverter. There is no ground wire in this cord. The unit has a screw marked with a grounding symbol on the outside of it's case near the floor. What is the proper way to ground this? It's a small screw. It could maybe handle a #10. What size ground is required? The cord has 4/0 conductors. I can post pictures if needed.
 
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jaggedben

Senior Member
Wow. Is this listed? Any instructions? What is the inverter? Doesn't sound right at all. My initial take would be that 250.122 applies and that the EGC needs to be in the cable.

(Also, why are you touching it? Sounds like the PV contractors job.)
 
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Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
(Also, why are you touching it? Sounds like the PV contractors job.)
A. I'm not touching it. I sub for the PV contractor (I am responsible for the utility connections) and he asked me how to do it. I told him I would consult the geniuses I know. Yes, I know the thread title threw you off.

B. I could touch it if I wanted to. I have an unlimited EC licence.
 

jaggedben

Senior Member
I guess my point was, if he spec'd and/or designed the system and he can't tell you, you may have a problem.
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
I guess my point was, if he spec'd and/or designed the system and he can't tell you, you may have a problem.
He has an electrical engineer that designs the systems and he builds them. I thought about suggesting he consult the electrical engineer, but I know he would be charged for that consult, whereas I'm feeling generous and will do it for the goodwill.
 

jaggedben

Senior Member
That's possible. I just don't know if it's necessary. Perhaps the ground is just to dissipate static. It's on the outside of the case. Is there a code reference for the need of grounding on a battery?
I don't know why the normal equipment grounding stuff wouldn't apply. Is the csse metal? Sounds like this thing wasn't designed with the NEC in mind.
 
If it's just a big battery why does it need grounded?
I agree. I looked through articles 480 and 720 and couldnt find anything requiring the case to be grounded. 250.96 may apply and require the case to be bonded, but I dont see that serving any purpose and, as someone who has lived off grid and dealt with storage batteries, really see it as creating more of a risk.
 

ActionDave

Moderator
Staff member
Location
Durango, CO, 10 h 20 min without traffic from wing
Occupation
wire pulling grunt
Probably no reason aside from 250.4. But you don't get to just ignore that, I don't think, unless you its listed and the instructions say that you don't have to or shouldn't.
250.4 is a general requirement and doesn't tell you anything about how to get there and may apply to something metal holding the battery, but I don't see how it would apply to a battery.
 

jaggedben

Senior Member
250.4 is a general requirement and doesn't tell you anything about how to get there and may apply to something metal holding the battery, but I don't see how it would apply to a battery.
We're not exactly talking about just a battery though. It might be more aptly described as an ESS. It's 18.5kWh.

 

Another C10

Electrical Contractor 1987 - present
Location
Southern Cal
Occupation
Electrician NEC 2020
that's possible. I just don't know if it's necessary. Perhaps the ground is just to dissipate static. It's on the outside of the case. Is there a code reference for the need of grounding on a battery?
It may simply be needed as a precaution not so much for the battery leaking to the chassis, similar I'd suppose to a pool pump, where usually a #10 or #8 Bonds the grounded reference to the exterior lug.
 

tortuga

Senior Member
Location
(44.057116, -123.103394)
Occupation
field supervisor
That section is referring to system grounding, not equipment grounding.
I see a battery as DC system first.
The larger current is when its discharging.
The charging current is likely small and protected at its source.
The point is moot now. The product has been inspected and passed. No ground wire was used.
Good glad it passed.
 
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