Hello from Essex! Anyone specialist in battery storage?

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tezla22

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Hi from Essex. part time sparky - fulltime office worker.
Was made furlough during the pandemic so spent a lot of time twiddling my thumbs, thought I'd do my inspection and testing, part p and 18th edition.
Now I'm back from furlough in my office job busier than ever, however developed a real interest in renewable energy.
Recently got an EV, purchased some decent 12KW batteries for the home along with a Solis inverter, just need to finish working out how I'm going to install it all.
Plan to harness night-time rate of 7p Kwh and discharge throughout the day.

Attached photos of my current setup and what I propose... probably overkill.
Cable run has a volt drop of around 1.51V
25mm SWA is there at the moment.

____________________________________________________________________________________________________________________
Thread moved, its not "introduce yourself" and it is not "solar"
 

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binky

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Hmmm, seen that on a certain FB page - I didn't bother to answer on there due to too many know it alls talking crap!

1/ what is your earthing arrangements on the incoming supply and does the 32A MCB share an RCD with any other circuit?
2/ you don't need SPDs, they are not compulsory.
3/ shed CU, is that an RCD main switch?
 

tezla22

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Hmmm, seen that on a certain FB page - I didn't bother to answer on there due to too many know it alls talking crap!

1/ what is your earthing arrangements on the incoming supply and does the 32A MCB share an RCD with any other circuit?
2/ you don't need SPDs, they are not compulsory.
3/ shed CU, is that an RCD main switch?
Thanks for the reply, ah yes I struggled big time with conflicting information.

1, The incoming it TNCS. Yes it shares the RCD with the whole of my ground floor.
2, Thankyou.
3, Shed CU - Yes RCD main switch and only have 4n circuits on that board. (Cheap BG Metal board).
 

binky

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TNCS should not be exported out of the Equipotential Zone of your house, so disconnect the earth in the garage and install a rod.

You don't want to be sharing RCd for the house with the garage - it's a bad idea at the best of times, but grid tied inverters have a requirement to shut down within 3 seconds in the event of a mains failure, RCDs are designed to shut down in milliseconds, so your RCd could trip but the inverter could still kill you!

If you are lucky you may have a consumer unit with 3 neutral bars, known as a high integrity board - move the garage MCB to the section not shared with the other circuits next to the main switch. If you havn't got one of those, then henleys and a switch-fuse is probably easier than changing the board. What I often use is a mini board with Main Switch and a MCB. Do connect the SWA earth at the house end, you still need an earth for that cable even if the earth isn't serving the shed

You could install an SPD, but that isn't mandatory until autumn this year.

RCD in garage is better not shared with the battery inverter for reasons staed above, I would replace that with a main switch and double pole RCBOs in the garage - they need to be double pole to meet requirements for TT.

You will need a comms cable for the amp clamp back in the house - mostly that is cat5 cable. I dont know why they insist on using cat5 as they only use 2 wires, but such is life :D.
 

tezla22

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Thank you, as it happens I have to replace the house consumer unit as were moving the location from under the stairs to the left hand wall as seen in the photo.

I will try and find a high integrity duplex / dual stacked board.

I can sort the rest no problem! Earth rod, main switch and double pole RCBOS on order.
 

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tezla22

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Here are my circuits for the new house... what do you think?


  • Smoke Alarms (Reason: Safety)
  • Driveway Lighting (Ground Fitted) - Radial (Reason: Had previous experience with water ingress tripping ground floor sockets constantly.)
  • House External Wall / Step Lighting - Radial (Reason: Potential to trip out and take out ground floor lighting.)
  • Single Driveway Socket - Radial (Reason: Valet cleaning car whilst at work, don’t want tripping power inside house.)
  • EV Charger 1 - Radial (Reason: Safety)
  • EV Charger 2 - Radial (Reason: Safety)
  • Ground Floor Lighting - Radial
  • Ground Floor Sockets (Excl Kitchen/Utility) - Ring
  • Hob 1 - Radial (Reason: Safety)
  • Oven 1 - Radial (Reason: Safety)
  • Oven 2 - Radial (Reason: Safety)
  • Kitchen Sockets - Ring (Reason: This will include Dishwasher, Potential ZIP Tap and Extractor Fan.)
  • Utility Room Sockets - Ring (Reason: This is due to having Tumble Dryer, Washing Machine and Iron.)
  • 1st Floor Sockets - Ring (Reason: Standard)
  • 1st Floor Lighting - Radial (Reason: Standard)
  • CCTV & Comms - Radial (Reason: Ensure no accidental tripping and loss of CCTV recording.)
  • Patio Heaters 6KW - Radial (Reason: Safety)
  • Hot Tub 32a Rotary - Radial (Reason: Safety)
  • Air Con 1 Rotary - Radial (Reason: Safety)
  • Air Con 2 Rotary - Radial (Reason: Safety)
  • Garden Steps Lighting - Radial (Reason - Water ingress and accidental tripping.)

So question is, do I put my outbuilding on an RCBO or do I just put the 25mm SWA powering my outbuilding into a Henley Block from a double pole isolator.
 

Richard-the-ninth

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Just saying..................................do NOT connect your smoke alarms to their own protective device, connect them to the lighting circuit. Reason being if on their own protective device, and it trips, you will never know until It's too late. Put them on with the lights and if they trip you will soon know because your lights are not working.
 

Fleeting

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Just saying..................................do NOT connect your smoke alarms to their own protective device, connect them to the lighting circuit. Reason being if on their own protective device, and it trips, you will never know until It's too late. Put them on with the lights and if they trip you will soon know because your lights are not working.
There is absolutely no requirement to do this under BS5839:6.
 

Fleeting

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TNCS should not be exported out of the Equipotential Zone of your house, so disconnect the earth in the garage and install a rod.

You don't want to be sharing RCd for the house with the garage - it's a bad idea at the best of times, but grid tied inverters have a requirement to shut down within 3 seconds in the event of a mains failure, RCDs are designed to shut down in milliseconds, so your RCd could trip but the inverter could still kill you!

If you are lucky you may have a consumer unit with 3 neutral bars, known as a high integrity board - move the garage MCB to the section not shared with the other circuits next to the main switch. If you havn't got one of those, then henleys and a switch-fuse is probably easier than changing the board. What I often use is a mini board with Main Switch and a MCB. Do connect the SWA earth at the house end, you still need an earth for that cable even if the earth isn't serving the shed

You could install an SPD, but that isn't mandatory until autumn this year.

RCD in garage is better not shared with the battery inverter for reasons staed above, I would replace that with a main switch and double pole RCBOs in the garage - they need to be double pole to meet requirements for TT.

You will need a comms cable for the amp clamp back in the house - mostly that is cat5 cable. I dont know why they insist on using cat5 as they only use 2 wires, but such is life :D.
You don't 'export' TN-C-S you are using an earth derived from such a supply. 'Equipotential zone' maybe a term often cited but it has not been included in BS7671 for many years. There is no reason why a supply cannot be used remote from a so called equipotential zone.
 

Richard-the-ninth

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There is absolutely no requirement to do this under BS5839:6.

I never said that there is such a requirement did I ? I just pointed out it is a better idea to connect smoke alarms to a lighting circuit for reasons I have already given.
 

binky

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You don't 'export' TN-C-S you are using an earth derived from such a supply. 'Equipotential zone' maybe a term often cited but it has not been included in BS7671 for many years. There is no reason why a supply cannot be used remote from a so called equipotential zone.
true, but why risk a potentially dangerous situation when installing a rod is so easy?

 

steptoe

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You don't 'export' TN-C-S you are using an earth derived from such a supply. 'Equipotential zone' maybe a term often cited but it has not been included in BS7671 for many years. There is no reason why a supply cannot be used remote from a so called equipotential zone.
So , you would have an earth that could be different to the potential mass of actual earth and you see no issue with that,?
Wonder what the DNO would say, you do realise you have to ask their permission to export a TNCS derived earth from the building it's supplied to.
The best option would be to install a PROPER PME system, with localised rods, but that involves a bit more in-depth earthing knowledge and testing.
 

steptoe

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Here are my circuits for the new house... what do you think?


  • Smoke Alarms (Reason: Safety)
  • Driveway Lighting (Ground Fitted) - Radial (Reason: Had previous experience with water ingress tripping ground floor sockets constantly.)
  • House External Wall / Step Lighting - Radial (Reason: Potential to trip out and take out ground floor lighting.)
  • Single Driveway Socket - Radial (Reason: Valet cleaning car whilst at work, don’t want tripping power inside house.)
  • EV Charger 1 - Radial (Reason: Safety)
  • EV Charger 2 - Radial (Reason: Safety)
  • Ground Floor Lighting - Radial
  • Ground Floor Sockets (Excl Kitchen/Utility) - Ring
  • Hob 1 - Radial (Reason: Safety)
  • Oven 1 - Radial (Reason: Safety)
  • Oven 2 - Radial (Reason: Safety)
  • Kitchen Sockets - Ring (Reason: This will include Dishwasher, Potential ZIP Tap and Extractor Fan.)
  • Utility Room Sockets - Ring (Reason: This is due to having Tumble Dryer, Washing Machine and Iron.)
  • 1st Floor Sockets - Ring (Reason: Standard)
  • 1st Floor Lighting - Radial (Reason: Standard)
  • CCTV & Comms - Radial (Reason: Ensure no accidental tripping and loss of CCTV recording.)
  • Patio Heaters 6KW - Radial (Reason: Safety)
  • Hot Tub 32a Rotary - Radial (Reason: Safety)
  • Air Con 1 Rotary - Radial (Reason: Safety)
  • Air Con 2 Rotary - Radial (Reason: Safety)
  • Garden Steps Lighting - Radial (Reason - Water ingress and accidental tripping.)

So question is, do I put my outbuilding on an RCBO or do I just put the 25mm SWA powering my outbuilding into a Henley Block from a double pole isolator.
As above, put your smoke detectors on with the lights,
and put your normal use sockets on radials, with one socket in each room on a different radial from the rest of them, that way at least on socket will work if the others trip out.
DP RCBOs, be very careful, most RCBOs available in the UK are NOT DP, they merely have L&N connected through them to detect imbalance.
 

tezla22

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Just saying..................................do NOT connect your smoke alarms to their own protective device, connect them to the lighting circuit. Reason being if on their own protective device, and it trips, you will never know until It's too late. Put them on with the lights and if they trip you will soon know because your lights are not working.
This is a good shout! However I was going to opt for the Nest Wired smoke alarms which self test daily and notify you via iPhone. They also have built in batteries.

I could still run them on the lights I guess.
 

tezla22

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As above, put your smoke detectors on with the lights,
and put your normal use sockets on radials, with one socket in each room on a different radial from the rest of them, that way at least on socket will work if the others trip out.
DP RCBOs, be very careful, most RCBOs available in the UK are NOT DP, they merely have L&N connected through them to detect imbalance.
I was reading that most people put 4mm radials in now however looking at the installation methods 2.5mm surrounded by thermal insulation can only take up to 4800w / 13.5a...

Will that be enough do you recon?

So what your saying is:

Bed 1, Bed 2, Bed 3, Bed 4, Bed 5, Landing - 1 Circuit / Ring
1 socket in each of the above rooms - 1 Circuit / Radial.
 

steptoe

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So what your saying is:

Bed 1, Bed 2, Bed 3, Bed 4, Bed 5, Landing - 1 Circuit / Ring
1 socket in each of the above rooms - 1 Circuit / Radial.
No,
Depending on how big the bedrooms are,
Bed 1 on a radial along with one socket in bed 2
Bed 2 on a radial along with one socket in bed 1
Bed 3 on a radial along with one socket in bed 4
.......

you get the jist

Tbh, you could maybe get away with 2 bedrooms on a radial

Oh, and fit AICO smoke detectors
 
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