generation meter installation

[rainman177]

how new?

 

[moggy1968]

it's been discussed on here at length that solar needs to be on it's own isolator, been best practice for sometime and you will have problems on your assessment if it goes on a shared RCD.
best way is to wire it so you can totally avoid RCDs

we were all novices once, sorry your experience on here hasn't been very good

 

[jason121]

how about combining your 2 AC strings into an AC isolator? 2cables into a terminal, one out. go for an oversized isolator, say a 64amp.

thinks he has RCD issue

 

[Earthstore]

Look up the threads on here about shared RCDs, if you have about 2 hours to read them.

It to summerise for you Solar PV should be on it's own RCD, that is if it needs one at all.

 

[moggy1968]

in that case I'm with you. split the tails into a henley block and put in a small CU, say a garage unit. you can use 16mm tails for the garage board.

 

[rainman177]

i do now yh then why is all my course note got a lead from the final ac isolator to cu
i did my course in september last year, my instructor said if there is a spare way use it as long as its rcd protected

 

[jason121]

Welcome to Solar nightmare, dont forget your paper trail, your H&S, overstay forms, survey forms, photos, structual reports, handover forms, commission forms, audit forms, the list is longggggggggg.

 

[jason121]

i do now yh then why is all my course note got a lead from the final ac isolator to cu
i did my course in september last year, my instructor said if there is a spare way use it as long as its rcd protected

old news, gotta keep up with legislation.

 

[rainman177]

reg 712.411.3.2.1.2 where the pv convertor is, by construction not able to feed dc fault currents into the electrical installation, an rcd of tybe b according to iec 62423 is NOT required

 

[jason121]

Thats for DC leakage, some inverters will trip the RCD, so thats why they have changed the rules.
The DTI guide and IET regs dont really gel
Also type B RCD are expensive and wont be in a standard fuse board

 

[rainman177]

is the dti guide mandatory or advisory/guidance. doesnt sound mandatory to me

 

[rainman177]

if the regs change ill change with them

 

[jason121]

GUIDE !!!! You takes the chance either he will pass it , you will be called back by customer because of nusiance tripping or will receive an NCR from the MCS inspector, which means you will have to alter it to pass inspection

 

[rainman177]

time for my bed im up at five with headache lol i managed to solve my problem i will certainly put it to my boss thanks jason all the best ttfn

 

[jason121]

Which make and type of inverter you installing ??

 

[rainman177]

agreed if he does i will have to alter it ill take my regs with me it is obviously a grey area agreed?

- - - Updated - - -


er a three kw omnik

 

[moggy1968]

your standard RCD is a type A (ignore the bit that says type B on your RCBO, thats refering to the MCB part of the RCBO) SOme inverters will prevent the correct operation of the RCD, so if one is needed it needs to be a type B for it to operate effectively.

This makes using an RCD a rather expensive business! It is generally considered rather bad form to use a shared RCD bevause of this, as it will be a type A but also because of other factors such as nuisence tripping and back feeding onto the installation, it's all very controversial and complex, so best just avoided!

most inverter manufacturers will also tell you in their instructions that you need a 100ma or even 300ma RCD so using a domestic 30ma is going against the manufacturers instructions, this is where nuisance tripping comes in.

as above better just to wire it so it doesn't need an RCD and avoid all the hassle!

P>S> yout titor was ill informed, out of date and ignorant it would appear not just of the requirements of solar, but basic wiring regs!

sadly, not unusual!

 

[moggy1968]

good luck, let us know how you get on!

 

[rainman177]

please understand im not trying to be blaze' about this its obviously a deep hole not one to get into the night before a job. the problem i have is the electrical wholesaler didnt supply use with the requested earth with the tails this morning amongst other things

 

[rainman177]

moggy are you suggesting i do not use an rcd at all, feels dangerous?