How is a EG4 Battery grounded without rack?

[timselectric]

Grounding is about personnel safety.
Not from the 48v battery. That won't kill you.

 

[bones1]

I am sure the majority of people do not do this. Or have heard of it.

 

[Brightside]

If something goes wrong inside the inverter. And AC power is conducted to the DC side. And if it finds its way to the battery case. It needs to trip the over current protection, before damage or injury occurs.
I know that it's a lot of if's, but that's what safety is about.

Thanks for the input.

That makes sense. I just needed to understand how this was determined.

 

[Shimmy]

What do people ground their 6 battery EG4 racks with?

It all comes down to what size breaker you provide for the battery bank as a whole. With 12xEG4 I would only do 400A max personally, so that would drive you to a #2 or #3.

If your 12 EG4's are in two independent racks with a 400A breaker protecting the battery cables then personally I would use a #2 from ground bus to the first rack and feed it through to the second rack. If you needed to install bonding jumpers for each individual battery then they would be #6 to the frame.

 

[Shimmy]

I am sure the majority of people do not do this. Or have heard of it.

And most inspectors would likely pass it as well. But, if you want to keep it safe it is best to properly bond things. Given some of the issues people have had with a lot of this equipment I tend to think that extra safety is likely a good idea.

I'm also surprised at how few people put a grommet around the battery cables as they enter or exit a metal enclosure. Doesn't make it a good idea.

 

[timselectric]

It all comes down to what size breaker you provide for the battery bank as a whole. With 12xEG4 I would only do 400A max personally, so that would drive you to a #2 or #3.

If your 12 EG4's are in two independent racks with a 400A breaker protecting the battery cables then personally I would use a #2 from ground bus to the first rack and feed it through to the second rack. If you needed to install bonding jumpers for each individual battery then they would be #6 to the frame.

Grounding and bonding is for people safety.
Basically if it's metal, and someone can touch it. It should always be safe to do so. Grounding the metal battery case and metal battery rack, has nothing to do with the battery voltage or amperage. It's for touch safety, against harmful voltages. (Higher voltage AC and DC power) if they were to find their way to any metal parts, that a person could touch.

 

[Shimmy]

Grounding and bonding is for people safety.
Basically if it's metal, and someone can touch it. It should always be safe to do so. Grounding the metal battery case and metal battery rack, has nothing to do with the battery voltage or amperage. It's for touch safety, against harmful voltages. (Higher voltage AC and DC power) if they were to find their way to any metal parts, that a person could touch.

Yes and no; bonding is for touch potential, but the way the code works it is also required as an ungrounded system to carry fault current... unless my code interpretation is wrong. For an ungrounded system the first action is to carry fault current, and the second to maintain touch potential.

(edit Your interpretation would be 100% correct though with UK standards.

 

[timselectric]

Yes and no; bonding is for touch potential, but the way the code works it is also required as an ungrounded system to carry fault current... unless my code interpretation is wrong. For an ungrounded system the first action is to carry fault current, and the second to maintain touch potential.

(edit Your interpretation would be 100% correct though with UK standards.

You are correct about carrying fault current. But it's not for the battery fault current. An ungrounded system above 60v is required to have fault protection on both conductors. Actually all ungrounded conductors, in a system. Fault current on the batteries would be from positive and negative coming together. Not to the case or rack, unless both positive and negative came into contact at the same time. In that case the battery protection (breaker, fuse, BMS) comes into play. Not the grounding or bonding.
At least, that's my interpretation of it.
But the NEC is all about interpretation. If the installer and inspector are in agreement, it passes.
If not, it doesn't. All of my DC systems have been inspected by Coast Guard, MSHA, and another acronym I can't remember. But not solar and not a regular electrical inspector. I'm sure that I would have no problems with the inspectors in my area, because I have long standing relationships with them. But, it could be very different in other jurisdictions.
Ok, this is very long winded for me. lol
I'm a less words kinda guy.
Peace out

 

[Dantheman]

what is the proper manner to ground eg4 batteries to chassis in mobile (rv or boat) applications? i am pairing the battery with a samlex evo 4024 and the mobile schematic in the manual has the negative grounded to chassis, does the dedicated ground connection on the eg4 satisfy that requirement? or do i ground both to chassis?

 

[timselectric]

what is the proper manner to ground eg4 batteries to chassis in mobile (rv or boat) applications? i am pairing the battery with a samlex evo 4024 and the mobile schematic in the manual has the negative grounded to chassis, does the dedicated ground connection on the eg4 satisfy that requirement? or do i ground both to chassis?

Both
If that's what the samlex requires.

 

[Dantheman]

Both
If that's what the samlex requires.

the samlex battery diagram doesnt have a dedicated grounding connection on the battery, it just lists the battery negative grounded to chassis - the eg4 manual says nothing about grounding in mobile applications, just grounding the chassis of the enclosure to the battery rack if you purchased one - i also want to make sure its ok to ground to same bus bar/chassis connection if i am to ground both
thank you for such a quick response tim, i appreciate it

 

[Nonlin]

This thread never got answered? It was said its on the front but mine is like the picture posted, nothing on the front and I just have one battery no rack... How do I ground the battery?

 

[timselectric]

This thread never got answered? It was said its on the front but mine is like the picture posted, nothing on the front and I just have one battery no rack... How do I ground the battery?

If the battery has the mounting flanges installed. You can use a bolt, nut, and star washer. And connect to the flange.
If not.
You can connect to one of the bolts that would be used to mount the flanges.
Existing bolt with a star washer.
The star washers purpose is to bite through the pant, and ensure that you have a good electrical connection with the battery case.