Ask an Electrician anything...

[Bert Cheese]

ruggedscotty said:

Bert Cheese said:

Here's a recent one under debate regarding a friend's summerhouse...approx 20 metres from the house if that makes a difference.
Summerhouse is fed from the main residence board with a run of SWA and has its own RCD protected circuit board for power & lights etc, an earth spike is present here and the earth lead in the house was left unconnected by the original electrician as he said the spike was sufficent for the summerhouse and would keep any problems from affecting the main house.

A couple of weeks ago they had their kitchen refitted involving a new circuit board being fitted, and were told by a different electrician the earth lead needs to be connected there from the summerhouse?
All has been fine so far, but the concern is that if the summerhouse trips for any reason in future the whole house would be blacked out with the indoor earth connected...any pointers appreciated thanks.

This is one that causes some issues - you need to know of the nature of the supply - If it is a TN-S supply then the electrician is right, no spike required. and the earth should be through to the outhouse. However if the house supply is TN-C-S then you need to have the outhouse earth free and a spike installed. Either one should be protected by a 30mA RCD. It may be protected by an RCBO at 30mA, however with outsides I always use a double pole RCD. I prefer to have both the live and neutral to be broken if the breaker trips.

The big issue is with a TN-C-S is that should the neutral into the house be broken then there is a good chance that the neutral will float upto the mains voltage. And as the earth and neutral is linked at the cable head the -C-S part combined and seperated at end user. the earth here will rise to same potential as the neutral. or 240v. which would mean 240v between any metal work in the summerhouse and the real muddy earth.

Id get your supply checked. to confirm that earth electrode in the house as that makes a difference.

the 18th edition wiring requirements, 2nd ammendment has said that you can provide an addittional provision at your main earth terminal by way of an earth rod. If this was o then you could connect the earth wire through to the outshouse.

411.4.2 It is recommended that an additional connection to Earth, by means of an earth electrode in accordance with Chapter 54, is made to the main earthing terminal. This recommendation does not apply to outbuildings of dwellings served by the installation.

Comment: In amendment 1 there was a note that referenced that an additional earthing connection could be made to the protective earth or PEN conductor. This has now been expanded upon and introduced as a recommendation. Essentially, with metal pipework and lead covered cables being replaced by plastic equivalents, the risks associated with PME supplies are increasing and customers are having to provide additional reinforcement to the DNO network by installing an additional electrode to the MET.

So by waht you have said - earth electrode in yopur house one at the summer house. If this is so then I would connect the earth between the summer house and the main dwelling.

Thanks for the swift response, a few points there regarding supply I wouldn't have thought about tbh...I used to install industrial refrigeration systems inc 3-phase contactors, control systems and such but "house bashing" as we casually referred to it seems to be something of a minefield these days.
I'll investigate and have a word with the householder who is a bit of a worrier.

[86]

Had a battery fitted last week to go with my solar panels. What checks would you expect the electrician to do to sign off for the regulations? Would it be reasonable to ask to see the test sheet ?

[ruggedscotty]

86 said:

Had a battery fitted last week to go with my solar panels. What checks would you expect the electrician to do to sign off for the regulations? Would it be reasonable to ask to see the test sheet ?

your test so you should get a copy. ask for them to explain the results and tests to you.

[silentbrown]

ruggedscotty said:

86 said:

Had a battery fitted last week to go with my solar panels. What checks would you expect the electrician to do to sign off for the regulations? Would it be reasonable to ask to see the test sheet ?

your test so you should get a copy. ask for them to explain the results and tests to you.

If you're just adding a 50V DC battery to the inverter is it even covered by regs? AIUI, none of the mains AC wiring is touched, assuming the inverter wasn't replaced.

[86]

silentbrown said:

ruggedscotty said:

86 said:

Had a battery fitted last week to go with my solar panels. What checks would you expect the electrician to do to sign off for the regulations? Would it be reasonable to ask to see the test sheet ?

your test so you should get a copy. ask for them to explain the results and tests to you.

If you're just adding a 50V DC battery to the inverter is it even covered by regs? AIUI, none of the mains AC wiring is touched, assuming the inverter wasn't replaced.

It is a Tesla Powerwall. From what I can see it has a new earthing spike which I imagine becomes the earth for the house if it runs as UPS. Looks like some new connections to meter and changes to fuse board

[silentbrown]

86 said:

It is a Tesla Powerwall.

That has built in DC/AC inverter so does connect directly to mains.

[ruggedscotty]

86 said:

silentbrown said:

ruggedscotty said:

86 said:

Had a battery fitted last week to go with my solar panels. What checks would you expect the electrician to do to sign off for the regulations? Would it be reasonable to ask to see the test sheet ?

your test so you should get a copy. ask for them to explain the results and tests to you.

If you're just adding a 50V DC battery to the inverter is it even covered by regs? AIUI, none of the mains AC wiring is touched, assuming the inverter wasn't replaced.

It is a Tesla Powerwall. From what I can see it has a new earthing spike which I imagine becomes the earth for the house if it runs as UPS. Looks like some new connections to meter and changes to fuse board

18th Edition Ammendment 2....

An earth spike can be added and connected to the consumers main earth terminal.

The issue is that you have to consider the neutral earth link where that is. As if you disconnect your mains through opening your isolator then your electrical system will operate as an IT system as there is no connection load side of the main isolator to reference the neutral to earth,

As said get confirmation on what was done and what tests were done, A simple battery addition no need but connecting an earth rod in you would be wanting to see some readings for your earths and for your earth loops etc.

[86]

ruggedscotty said:

86 said:

silentbrown said:

ruggedscotty said:

86 said:

Had a battery fitted last week to go with my solar panels. What checks would you expect the electrician to do to sign off for the regulations? Would it be reasonable to ask to see the test sheet ?

your test so you should get a copy. ask for them to explain the results and tests to you.

If you're just adding a 50V DC battery to the inverter is it even covered by regs? AIUI, none of the mains AC wiring is touched, assuming the inverter wasn't replaced.

It is a Tesla Powerwall. From what I can see it has a new earthing spike which I imagine becomes the earth for the house if it runs as UPS. Looks like some new connections to meter and changes to fuse board

18th Edition Ammendment 2....

An earth spike can be added and connected to the consumers main earth terminal.

The issue is that you have to consider the neutral earth link where that is. As if you disconnect your mains through opening your isolator then your electrical system will operate as an IT system as there is no connection load side of the main isolator to reference the neutral to earth,

As said get confirmation on what was done and what tests were done, A simple battery addition no need but connecting an earth rod in you would be wanting to see some readings for your earths and for your earth loops etc.

Thank you

[86]

After installing solar, a battery and car charger I’m told I need to upgrade from an 80amp to 100 amp fuse. Before doing so Network Power says an electrician / energy supplier needs to make sure I have 25 mm meter tails. Can anyone tell from this photo please

[Sir Bagalot]

If you were changing these



Old style lampost light, to something a tad more modern, ie LED lights



Effectively it's simply a new head.

Excluding the cost of hiring a cherry picker, what sort of cost is involved per light. Supply and fit. There will be 8 of them to do.

[megaphone]

Sir Bagalot said:

If you were changing these



Old style lampost light, to something a tad more modern, ie LED lights



Effectively it's simply a new head.

Excluding the cost of hiring a cherry picker, what sort of cost is involved per light. Supply and fit. There will be 8 of them to do.

I did 20 off a scaff tower and ladders. . Heads can vary in cost, £100-£200 each. You get different light patterns and outputs, do your research. Do they need a photo cell so they come on when dark? You need to check the post diameter, 75mm is common, but they could be 100mm, some heads need an adaptor.

Pretty easy to swap, you need to pre-wire them and then drop the flex down the post. I did 20 in a day and half. Had a colleague connecting them up at the bottom.

https://www.kellwoodlighting.co.uk/product-range/a...

[Sir Bagalot]

megaphone said:

Sir Bagalot said:

If you were changing these



Old style lampost light, to something a tad more modern, ie LED lights



Effectively it's simply a new head.

Excluding the cost of hiring a cherry picker, what sort of cost is involved per light. Supply and fit. There will be 8 of them to do.

I did 20 off a scaff tower and ladders. . Heads can vary in cost, £100-£200 each. You get different light patterns and outputs, do your research. Do they need a photo cell so they come on when dark? You need to check the post diameter, 75mm is common, but they could be 100mm, some heads need an adaptor.

Pretty easy to swap, you need to pre-wire them and then drop the flex down the post. I did 20 in a day and half. Had a colleague connecting them up at the bottom.

https://www.kellwoodlighting.co.uk/product-range/a...

So you're saying £150 ish supplied and fitted each + VAT. Cherry picker hire on top

[megaphone]

Sir Bagalot said:

megaphone said:

Sir Bagalot said:

If you were changing these



Old style lampost light, to something a tad more modern, ie LED lights



Effectively it's simply a new head.

Excluding the cost of hiring a cherry picker, what sort of cost is involved per light. Supply and fit. There will be 8 of them to do.

I did 20 off a scaff tower and ladders. . Heads can vary in cost, £100-£200 each. You get different light patterns and outputs, do your research. Do they need a photo cell so they come on when dark? You need to check the post diameter, 75mm is common, but they could be 100mm, some heads need an adaptor.

Pretty easy to swap, you need to pre-wire them and then drop the flex down the post. I did 20 in a day and half. Had a colleague connecting them up at the bottom.

https://www.kellwoodlighting.co.uk/product-range/a...

So you're saying £150 ish supplied and fitted each + VAT. Cherry picker hire on top

That will be just the cost of the parts, I'd allow £200 per post. Then labour on top. I did it as part of a larger project. 8 posts, probably cost a day's work for a man and a boy.

[RichB]

I want to place an outside lamp on the corner under the wisteria. The only way to get power down is from through the soffit from a socket in the loft. I could use a RCB plug in the loft and obviously a suitable outside switch IP66 rated. But, is there a particular type of cable I should use? I aim to hide the wire behind the downpipe.

[DaveCWK]

86 said:

After installing solar, a battery and car charger I’m told I need to upgrade from an 80amp to 100 amp fuse. Before doing so Network Power says an electrician / energy supplier needs to make sure I have 25 mm meter tails. Can anyone tell from this photo please

They look like 25mm tails to me. Surprised this is an absolute requirement tho -my house has 16mm tails and a 100A fuse.

[ruggedscotty]

RichB said:

I want to place an outside lamp on the corner under the wisteria. The only way to get power down is from through the soffit from a socket in the loft. I could use a RCB plug in the loft and obviously a suitable outside switch IP66 rated. But, is there a particular type of cable I should use? I aim to hide the wire behind the downpipe.

external influences? secateurs, hedge trimmers? degradation due to UV?

I put one in a few years ago,remote controlled and hole through the wall. light mounted on wall and controlled from a remote control switch.

hiding cable behind downpipe.... nah... get it done right if you can through a hole twin and earth ok, longish runs use swa...

[AW10]

Wifi controlled switch via phone app, Alexa, etc.

[RichB]

AW10 said:

Wifi controlled switch via phone app, Alexa, etc.

switch isn't the issue. It's getting the power to the lamp fitting. There's no access behind the position on the wall. It doesn't come through to the room behind, there's a cavity there with a soil pipe enclosed in it. Hence why I think it needs to run on the exterior of the house.

[ruggedscotty]

RichB said:

AW10 said:

Wifi controlled switch via phone app, Alexa, etc.

switch isn't the issue. It's getting the power to the lamp fitting. There's no access behind the position on the wall. It doesn't come through to the room behind, there's a cavity there with a soil pipe enclosed in it. Hence why I think it needs to run on the exterior of the house.

swa then

[RichB]

ruggedscotty said:

RichB said:

AW10 said:

Wifi controlled switch via phone app, Alexa, etc.

switch isn't the issue. It's getting the power to the lamp fitting. There's no access behind the position on the wall. It doesn't come through to the room behind, there's a cavity there with a soil pipe enclosed in it. Hence why I think it needs to run on the exterior of the house.

swa then

Indeed, I thought so... thanks...