Any recommendations for some simple guidance on solar PV please?
I want to get a better idea of what may (or may not) be feasible at home before I obtain quotes. So not too simple, but I think that the Code of Practice might be too detailed and technical.
A simple question, but Uncle Google does not help.
I gather that there is normally an a.c. isolator means of isolation adjacent to the inverter. What sort of cable is normally used to connect that to a CU please? T&E?
I ask simply because I want to get my installation "solar-ready" as far as possible.
462.2 gives "examples" of:
- Located within a lockable space or lockable enclosure
- Padlocking
- Located adjacent to the associated equipment
Presuming the installation extends beyond the immediate area where the CU is installed, the 3rd option is out. So while BS 7671 always leaves the door open to ingenious other solutions, what other practical options are open to the domestic electrician?
- Andy.
what other practical options are open to the domestic electrician?
There are locks and there are locks.
Suitably skillful thieves can overcome almost all of them.
A good bash with a fist would overcome a dolly lock. A hammer might be required for one of those yellow rotary things. You would need a good hacksaw or a disc cutter for an Eaton Glasgow.
The point is that all of them prevent inadvertent closure of the switch: there has to be a deliberate act to achieve it. The only difference is the amount of effort. But doesn't the same apply to the lock on your shed?
my inverter (and battery) will be in the same store room as the top floor's DB
Worth looking at PAS63100 for battery placement
According to the PAS 63100:2024 standard for home battery storage in the UK, batteries should ideally be installed outdoors, such as in a garage, outbuilding, or in a dedicated external cabinet. This is now depedant of battery chemistry type/makeup
It is probably advisable to have an EICR/Periodic inspection and test to check on the current condition of the install first and ask to check if you have
RCBO or Bidirection MCB for the dedicated circuit you plan to use for the Solar PV/Battery?inverter setup
Is there an SPD type 2 present and in good working order. (Not all flag colours are the same meaning)
On a side note if you are going to have Solar PV/Battery/Inverter installed please check your smoke/heat alarms and positions. 10 years is normal replacement date for domestic dwelling but the alarm/sensor should normally advise of replacement date on a sticker on the unit. Additional alarms maybe required due to the proposed extra kit (Solar PV/Battery/Inverte) and they should be inter-linked
It is probably advisable to have an EICR/Periodic inspection and test to check on the current condition of the install first and ask to check if you have
RCBO or Bidirection MCB for the dedicated circuit you plan to use for the Solar PV/Battery?inverter setup
Is there an SPD type 2 present and in good working order. (Not all flag colours are the same meaning)
Sergio, thank you. The installation is < 10 years old and in good order.
There will be an MCB for the inverter circuit in a 4-way DB nearby. That has a 16 mm² distribution circuit from an MCB in the main house board. All the final circuits are on RCBOs. SPD is fitted.
There will be an interconnected smoke alarm in the store room.
So, plug and play for the solar installer. :-)
According to the PAS 63100:2024 standard for home battery storage in the UK, batteries should ideally be installed outdoors, such as in a garage, outbuilding, or in a dedicated external cabinet.
Indeed, but with the caveat, "Where practicable" (6.5.1). I am not sure that a wall two storeys up is practicable.
This is now depedant of battery chemistry type/makeup
There it gets a bit confusing.
6.5.1 continues, "b) with ventilation according to 6.5.4".
6.5.4 NOTE 1 Guidance on and further requirements for ventilation are provided in BS EN IEC 62485 series.
BS EN IEC 62485-1:2018 refers to some types of batteries producing gas and risk minimisation by, amongst other things, ventilation (section 9).
BS EN IEC 62485-2:2018 refers to hydrogen being emitted during charging due to electrolysis (7.1) and gives a formula for ventilation (7.2). However, the values given are for lead acid and NiCd batteries.
BS EN IEC 62485-5:2021 deals with Safe operation of stationary lithium ion batteries. There is no mention of gaseous emissions save under fault conditions.
So, is there a risk of hydrogen emission from a healthy lithium battery please?
My understanding was no H2 emissions from lithium ion during normal charging (at least for LiFePO4 types) - seems to be the general consensus too - e.g. https://safetyinspectors.co.uk/2024/01/19/how-does-the-risk-of-hydrogen-gas-h2-emission-compare-between-lithium-ion-and-lead-acid-batteries-during-charging/
- Andy.
hydrogen emission from a healthy lithium battery?
No, none at all, they are sealed
But an abused lithium battery can liberate a lot worse where lead acid and NiCd used to just electrolyse water to the point of drying out and ceasing to work,
Lithium if over - charged can be far more spectacular than that... . The battery enters a state where it produces its own heat, oxygen, and fuel, and resulting in fire... see any no, of youtube videos....
Mike
The battery doesn't even have to be abused to fail, there's been incidents in continental Europe where home batteries have developed a in-service fault and failed, starting fires or in some cases explosively, there's been a few incidents reported of lithium ion home batteries causing significant structural damage.
It's for this reason I would be very wary about ever locating the battery inside the building. Installed on an outside wall, any energy release is outside the property and if the battery does start off-gassing, releasing flammable gasses then there's no confinement to allow an explosive atmosphere to form, the gasses naturally disperse.
And thinking longer term, I wonder how all of these batteries installed in people's homes are going to be safely managed as they steadily degrade and reach end of life. These are not routinely maintained, tested or inspected. Will they all gently degrade and simply fail in a benign way, or be safely shut down by protection or internal safety measure. Or as the cells, or rather strings of cells, start to degrade will we start to see more batteries failing in a hazardous way.
The only batteries that I know of that will out gas during charging are lead acid. Some people will still be using them, mainly for off grid applications.
If your lithium batteries are giving out gas, it's time to call the fire brigade.
And thinking longer term, I wonder how all of these batteries installed in people's homes are going to be safely managed as they steadily degrade and reach end of life.
Thank you folks for confirming what I thought.
That's an interesting point. Will batteries simply lose the ability to store power, in which case they will need to be replaced at some point?
My fire alarms have a "sell-by" date on them, so they have to be replaced after 10 years. A typical warranty is 10 years, so perhaps routine replacement should be considered at that stage?
And thinking longer term, I wonder how all of these batteries installed in people's homes are going to be safely managed as they steadily degrade and reach end of life.
Thank you folks for confirming what I thought.
That's an interesting point. Will batteries simply lose the ability to store power, in which case they will need to be replaced at some point?
My fire alarms have a "sell-by" date on them, so they have to be replaced after 10 years. A typical warranty is 10 years, so perhaps routine replacement should be considered at that stage?
There's no way a rechargeable battery will last forever. There will be a warranty, maybe 10 years.
In most cases, the battery will gradually deteriorate rather than failing suddenly.
Newer chemistries, such as lithium iron phosphate or sodium ion may well last longer than the old lithium ion.
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