Earthing

[spacebiscuit]

I'm thinking I should earth down my PV on my flat roof. Can I use 6mm cable - the 10mm seems like it will be hard to work with but I believe is what regs state. Would 6mm do anything in the event of say a lightening strike. My thinking is that 6mm is better than nothing at all?

Other question - does it have to earth down to a rod in the ground or can I tie it into the house somewhere which is already earthed down?

For the record I have retrofitted my panels myself, I'm not sure that they were previously earthed down.

 

[Geoff1946]

Nothing will protect you from a direct lightning strike, so I wouldn't worry about that.
I'll let more knowledgeable members comment on the need for any earthing, (bonding?) but I know my professionally installed system has none.

 

[spacebiscuit]

Ah ok I thought with a lightening strike it was intended to protect the kit rather than me?

Interested to here thoughts - thanks!

 

[7029 Dave]

Ah ok I thought with a lightening strike it was intended to protect the kit rather than me?

Interested to here thoughts - thanks!

Do you have an SPD fitted in your CU

 

[Andy™]

Ah ok I thought with a lightening strike it was intended to protect the kit rather than me?

Interested to here thoughts - thanks!

if you get a direct hit, earthing is going to do nothing. kit will be destroyed either way

 

[binky]

there was never a requirement to earth PV, except under some odd circumstances which I wont go into. Adding an earth bond may actually attract a lighting strike - easier path the earth. The only thing an earth bond does offer is easier fault finding in the event of an insulation fault with the array.

 

[SPECIAL LOCATION]

I'm thinking I should earth down my PV on my flat roof. Can I use 6mm cable - the 10mm seems like it will be hard to work with but I believe is what regs state. Would 6mm do anything in the event of say a lightening strike. My thinking is that 6mm is better than nothing at all?

Other question - does it have to earth down to a rod in the ground or can I tie it into the house somewhere which is already earthed down?

For the record I have retrofitted my panels myself, I'm not sure that they were previously earthed down.

Which are the regs you are referring to that suggest a 10mm is required for a lightening conductor??

 

[runningpiglet]

there was never a requirement to earth PV, except under some odd circumstances which I wont go into. Adding an earth bond may actually attract a lighting strike - easier path the earth. The only thing an earth bond does offer is easier fault finding in the event of an insulation fault with the array.

I think the bit about "attracting a lightning strike" has been disproved now. But you are right that domestic PV is not generally earthed.

 

[Badger]

If you have enphase micro. Inverters which operate at reduce dc voltage on the array as per solar panel is a Seperate inverter underneath is there any other things re earthing that is needed to be done as the voltage on the solar pv will be a max of around 60 ish volts dc not several hundreds in dc volts

 

[binky]

I think the bit about "attracting a lightning strike" has been disproved now. But you are right that domestic PV is not generally earthed.

it was only ever a slim chance.

 

[UNG]

Lightning protection as I was told many years ago by a guy in the techinal dept of a large well known lightning protection manufacturer is a dark art where doing nothing can be safer than installing a lightning protection system that could be more dangerous if a strike occurred

I'm thinking I should earth down my PV on my flat roof. Can I use 6mm cable - the 10mm seems like it will be hard to work with but I believe is what regs state. Would 6mm do anything in the event of say a lightening strike. My thinking is that 6mm is better than nothing at all?

Other question - does it have to earth down to a rod in the ground or can I tie it into the house somewhere which is already earthed down?

For the record I have retrofitted my panels myself, I'm not sure that they were previously earthed down.

Given that the down lead / conductor on a lightning protection system is normally a 25 x 3mm copper tape (75mm² CSA) I think 6 or 10mm² might be somewhat under sized for the task.
I would suggest unless you have a good understanding of lightning protection and the placing of earth rods to minimise the risk of the step potentials that may occur during a lightning strike then my advice would be to leave well alone