NEC requirements for cables from a battery bank to the inverter

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ryangittens

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Per my understanding of NEC 2017 706.32 flexible cables can only be used within a battery bank enclosure. From the battery bank to the inverter, it appears that a chapter 3 wiring method is required.

That said, from all the install pictures I've ever seen involving battery banks, the conductors from the battery banks to the inverters are never in conduit and appears to be the same flexible cables used to interconnect the batteries. How is this compliant? Does the fact that the battery bank is operating below 50V have anything to do with it?
 
This recent thread had some good info relating to this.

Solar Battery Cable- SGT SAE J1127 Battery Automotive Cable

Hello, First time here. New project involving off-grid solar upgrade. What is NEC code regarding the type of rating to use for solar battery cable? My technician prefers the SGT SAE J1127 Battery Automotive Cable. A colleague brought up NEC Code and proposed XLP/USE-2/RHH/RHW-2 WIRE cable...
xenforo.mikeholt.com

I think the truth is that many early off-grid solar systems were either not inspected or were given a pass by inspectors. The latter would happen either because they lacked the expertise to call for corrections, or maybe they gave a broad reading of 90.4's allowance for non available products.

With the advent of higher voltage batteries and ESSs with integrated inverters, I wouldn't necessarily expect things to change. On the other hand, there does seem to be more adoption of lithium batteries in 48V systems so maybe that will drive availability of more legit conductors for this application.
 
@GoldDigger @jaggedben thanks for all the info.

So based on all that, the options are to use TC-ER cable without conduit or flexible dual-rated cable that still has to be in conduit.

The other thing is that most of the inverters aren't even capable of accepting the conduit size that would be required for these large battery wires.
 
ryangittens said:
@GoldDigger @jaggedben thanks for all the info.

So based on all that, the options are to use TC-ER cable without conduit or flexible dual-rated cable that still has to be in conduit.

The other thing is that most of the inverters aren't even capable of accepting the conduit size that would be required for these large battery wires.
Click to expand...
Presumably you are using large wire to limit voltage drop. If so add a junction box to transition to smaller wires just before terminating at the inverter.
Maybe use Polaris connectors.
 
GoldDigger said:
Presumably you are using large wire to limit voltage drop. If so add a junction box to transition to smaller wires just before terminating at the inverter.
Maybe use Polaris connectors.
Click to expand...

He did mention 50V so I think we may be talking about large wire just for the amps. Some of these systems have 50V lithium batteries connected to inverters with continuous output of 12kW, e.g. Sol Ark. So that needs some big battery cables.
 
jaggedben said:
He did mention 50V so I think we may be talking about large wire just for the amps. Some of these systems have 50V lithium batteries connected to inverters with continuous output of 12kW, e.g. Sol Ark. So that needs some big battery cables.
Click to expand...
But I would then expect that 12kW inverter to have a terminal box that can accommodate that size wire in conduit.
 
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