rcd ground mount 4000 tl ............................. sorry im new

[toffeeman]

Hi guys and girls , just installing a 4000tl and a groundmount system , i have used an earthrod to earth the frame and have a fuse board next to the inverter, we have a pme earthing from house to the TL fuseboard which i was going to divorce at the board . i know you guys have gone over this a few times but im new , my question is what R C D should i use. Im a sparks so was thinking a 30ma but after reading some posts this seems a bad idea ? any help wold be great

 

[LightGEN]

The 4000TL has an integrated 100mA RCD, so you may not need to add an additional RCD, only doing so if the nature of the circuit between the fuseboard and the inverter calls for one to be added - if it does, the RCD should be a 100mA device, as specified on page 26 of the 4000TL installation manual (Version 3.0)

SMA publishes a useful document about RCD selection, here - http://files.sma.de/dl/7418/RCD-UEN103120.pdf

Although slightly off the topic of your original question, a recent discussion, on this forum, about RCD protected bus-bars, generation systems and their implications for additional circuits connected to the RCD protected bus-bar, may be valuable reading, here - http://www.electriciansforums.net/p...en-energy-forum/47651-rcds-photovoltaics.html

 

[toffeeman]

Thanks , think i have cracked it, planning on exporting the p.m.e to the ground mount, plus a 100ma rcd on the fuseboard side, with 10ml earthbond between mounts, This doesnt feel right to me,but after alot of research seems to be best option open to me , i know the rcd is not needed with this earthing system but i dont like the thought of exporting pme, (belt and braces) . would apperciate anyone thoughts on this

 

[moggy1968]

you can't export the earth on a PME. you can only earth this through a spike.

 

[SolarCity]

you can't export the earth on a PME. you can only earth this through a spike.

I'd say go for an earth spike too.

 

[BruceB]

you can't export the earth on a PME. you can only earth this through a spike.

Whilst it is sometimes not a good idea to export a PME, there is no regulation preventing it and it is often a good way to get an earth somewhere provided you understand the bonding requirements. Certainly there is nothing wrong with using the PME earth to protect the armoured(?) cable leaving the house in this instance.

 

[moggy1968]

you cannot export the earth on a PME outside the equipotential zone. The DNO don't allow it.
You aren't even supposed to earth an array on the roof through the PME so a ground mount system is definately out!
earthing the household end of the SWA is an entirely different thing and not what was in the original post.

 

[LightGEN]

A more detailed system description might be useful:-

a) Describe the connection arrangement at the main CU - a dedicated MCB attached to a non-RCD protected bus-bar perhaps?
b) Where is the sub-CU located and how is it connected to the main CU? Cable type?
c) Where is the inverter located - inside or outside and how is that connected to the sub-CU?

 

[BruceB]

you cannot export the earth on a PME outside the equipotential zone. The DNO don't allow it.

A folk myth believed by many. However, none of the current UK DNOs has such a general rule as far as I am aware. I would be happy to be proved wrong, but I have looked within the last year.

You may be experienced enough to remember back to the days of the Electricity Supply Regulations and PME Regulations, but they have long since been superceded by the ESQC Regulations.

 

[toffeeman]

thanks guys . if i go for an earth spike with the 4000tl i will need to use a 100ma rcd to avoid tripping , so i will be down to a 5s shock not 0.4 sec . to be honest,like i said in orginal post not happy with pme. but as bruce says cant find anything aganist doing this, unless i get another inverter, i believe this the only option i have left, i have wired a few swimmimg pools with pme and thats commen practice, i belive i need to use 10ml cpc to earth the frames. any other suggestion, ideas, issue please could you post, thanks for your help