Help with all the kit I need for connecting Batteries to home

Heedtheadvice

Qyburn said:

Heedtheadvice said:

Similarly there can be very high battery currents flowing ( well above nominal) and the expected 60 or 70 amp current requires a DC side100A breaker.

The battery is rated for 200A charge or discharge. But I note it has an integral 250A DC isolator, is an external isolator also required.

Given that the battery has a functional on/off switch and a separate large current breaker then that would seem to meet the need.

However given the guidance for isolation based upon the BS it would be better to have a separate isolator to cope with some circumstances for several reasons.

An isolator can be positioned in an obviously visible location at just below eye level and be labeled as a battery DC isolator. 

One might consider that the inbuilt breaker does the job but it does not isolate the battery and it's cable terminations entirely from the inverter ( there could be power from the inverter supplied via the cables especially under fault conditions).

Some electricians ( and others ) are not very familiar with battery storage systems ( though they now ought to be!) and having a clearly labelled isolator helps safety. It might be argued that the installer/owner will be aware but it may be others who need to work on the power system.

If there are more than one battery banks then a single point isolator to/ from the inverter is more convenient and possibly more obvious.

A single point isolator needs to cope with the combined  higher current.

Most DIYers would think it overkill and some electricians too but it is certainly sensible for clarity, visibility and labelling. On a single battery bank ( with such  a designed  breaker as is in the Fogstar being discussed in this thread ) it would not seem to be essential but as pointed out above there are advantages in having a dedicated isolator.

I would point out that I have not read the latest BS ( wiring regs) and would be more than happy for a competent person to comment. I also expect the BS or guidance docs to be updated. There have already been two safety related incidents reported ( that I am aware of via the IET website ) regarding confusion over renewable generation/ESS isolation.

Qyburn

I believe the installation would need DNO permission or notification. It would specifically be the inverter they're concerned about since that's the power source connected in parallel with their supply.

TroubledTarts

Thanks all, slowly piecing this together and do have some neighbour electricians so will pester them as well and see the art of the possible.

greenbee

Qyburn said:

I believe the installation would need DNO permission or notification. It would specifically be the inverter they're concerned about since that's the power source connected in parallel with their supply.

I was talking to my electrician about exactly this today and he confirmed the need for DNO approval.