Is there any benefit to fusing the negative battery terminals or is Positive good enough?

As long as the circuit is broken, I think it should be fine

Or

is it a safety thing to have a total disconnection from the battery ?

When looking at member installations , I see both configurations , Negative Unfused and Fused

 

Source : https://powerforum.co.za/topic/2322-youdas-off-grid-lab/page/2/

 

Source: https://powerforum.co.za/topic/20134-sunsynkbsl-slimline/

 

Edited June 28, 20233 yr by Dieter

On 2021/04/04 at 7:23 PM, Shadders said:

Not necessarily true that only fusing the positive would provide the necessary protection. If your positive terminal was earthed the fuse wouldn't fail if there was a fault current from the negative terminal to earth. In most systems you earth one of your potentials and then your protection can safely be installed on the other potential. Quite a few inverters earth the negative battery DC or recommend it, but not all, so it is safer to have a fuse on both lines in case your equipment is set up differently.

Source: https://powerforum.co.za/topic/8633-why-do-we-use-a-fusecircuit-breaker-on-both-the-dc-positive-and-negative-wires/

 

Edited June 28, 20233 yr by Dieter

On 2023/06/28 at 11:52 AM, Dieter said:

Is there any benefit to fusing the negative battery terminals or is Positive good enough?

There is non, but the SA Installation regulations require it - so we have been told.

2 hours ago, Beat said:

There is non, but the SA Installation regulations require it - so we have been told.

Sans regs specify disconnect of pos and neg either isolation rated dc breaker or double pole dc disconnect fuse.

This is the most recent (2017) published SANS doc I could find online (https://ekurhulenitech.co.za/wp-content/uploads/2022/01/1104041211040432.pdf😞

So, unless one of the battery terminals is grounded (which can generally not be done with inverters), then both must be fused, and both must have a disconnect.

If one terminal is grounded, then it MUST NOT be fused or have a disconnect.