solar pv electric shock

[sparkybob1]

I have installed a 4kw solar array. The customer says they are getting an electric shock from the tin roof that the panels are mounted on. I have been back twice and retested the strings, the ac, and checked the connections. Both times I couldn't find anything wrong but the customer is certain it is electric shock! Has anyone had this problem before?

 

[telectrix]

is the metal roof earthed/bonded?

 

[shanky887614]

I have installed a 4kw solar array. The customer says they are getting an electric shock from the tin roof that the panels are mounted on. I have been back twice and retested the strings, the ac, and checked the connections. Both times I couldn't find anything wrong but the customer is certain it is electric shock! Has anyone had this problem before?

most likely static, people complain about anything and everything but nothing you can do about it because its discharging from them to the roof.


remember solar panels are dc so would sting. do you think they would leave it if it was a problem with the string?

 

[sparkybob1]

No earth bonding to the tin roof, would this sort any issues? is it possibly a static build up?

 

[shanky887614]

No earth bonding to the tin roof, would this sort any issues? is it possibly a static build up?

because you tested and no faults, to me it seems that there getting a static discharge from themselfs to the roof (least resistance)


if there is no bonding then it can only be going from them to the roof as electricity takes the easiest route.

 

[Gavin A]

capacitance - look it up, SMA do a good technical briefing on it.

Have you tested continuity from rails to MET? Fair chance with a metal roof covering that there's continuity there, in which case...bonding as per MCS guidance.

I'm assuming it's a TL inverter - this is pretty normal stuff, just amplified due to the conductivity of the roof covering which makes the capacitance worse. Just instruct the customer to turn off the DC isolator before accessing the roof. The leakage currents shouldn't be anything like strong enough to cause anything other than a mild tingle, the danger really resides in the potential for this to cause someone to fall of a ladder and hurt themselves that way.

 

[pactrol]

Hi

it may be a bit more serious than falling off a ladder if this is an agricultural environment with livestock involved as they are more sensitive than humans due to having 4 points of contact with earth.
just a thought.

 

[Gavin A]

if you've got cows on your tin roof then you've got bigger problems to worry about than them getting a bit of a tingle off the panels

 

[BruceB]

Indeed
Brazilian man dies after cow falls through his roof on top of him - Telegraph

 

[pactrol]

if you've got cows on your tin roof then you've got bigger problems to worry about than them getting a bit of a tingle off the panels

yes well there,s always One with cows on his roof isn,t there

if you have a metal roof there's a good chance it has metal supports hence Your cows can become another path to earth
but as you say if your keeping your cows on the roof then its not a problem ( Faraday cage effect )

 

[Earthstore]

This thread is 9 months old, I would have thought that the cows, if there were any, would have learnt to stay away from the roof by now....

 

[SolarCity]

Isn't there some guidance in the new MCS guide about dealing with cattle grazing on top of tin roofs?

 

[Gavin A]

yes well there,s always One with cows on his roof isn,t there

if you have a metal roof there's a good chance it has metal supports hence Your cows can become another path to earth
but as you say if your keeping your cows on the roof then its not a problem ( Faraday cage effect )

metal framed buildings are usually incredibly well earthed via their metal legs IME.

 

[pactrol]

for the most part that is true though not always the case depends on the ground type

 

[Earthstore]

So, would the cows that had not learnt to stay away from said roof be standing on a different ground to the one that the building is sitting on, it is still a 9 month old thread.....