RCD protection for PV?

[fiardor]

It kind of depends on your interpretation.
Does this mean an RCD must be fitted to TL inverters, or just that if one is fitted it must be a type B? My interpretation is the latter.

Transformerless inverters mean they dont have galvanic isolation between ac and dc so i would say that you should provide rcd protection and bond the array for TL inverters

 

[BruceB]

You can debate whether you should have an rcd with transformerless and I would be interested in the reasons. I am not sure I know enough about the internals to argue from a position of strength though.

What I can say, I think authoritatively, is that there is no regulation requiring an rcd with transformerless. The requirement in 712.411.3.2.1.2 refers to 'rcd to provide fault protection by ADS' which would apply for:
- TT
- Zs too large at inverter (unlikely for voltage drop reasons on non-TT)

 

[fiardor]

The DTI guide as moggy says can sometimes be open to interpretation.

In fact so can the regs LOL

And my misssus come to think of it...........

She says dont touch but i know what she really means :53:

PMSL

 

[GaryM]

Can we talk about what deems somebody to be competent? PMSL

Formal qualifications and experience

 

[SibertSolar]

The excerpt from the DTI guide assumes that you are assessing the need for and RCD for ADS. If you do, and IF you do not have galvanic isolation (simple separation) between the DC and AC circuits, then you should choose a Type-B RCD. It is not a definitive "you must use a Type-B RCD for any TL inverter installation". I believe Bruce has it right in his post above. The debate starts from there really as to whether the TL inverter manufacturer's statements regarding the need for a Type-B RCD or not are all-encompassing or not..... the outcome of such debate can have an impact on the general use of Type-B RCDs for all TL inverter installations, regardless of the need for ADS or otherwise.

 

[fiardor]

Formal qualifications and experience

EH ERRR

Sorry Gary but that was my point,

The regs make no reference to formal qualifications in their definition of competent only technical knowledge and practical skills are enough to qualify as a competent person.............apparently.

 

[ak492158]

Thanks very much for your help guys.

The supply was TNCS with good Ze, so I used a Garage unit with 20A MCB and a built in generationn meter.

 

[moggy1968]

EH ERRR

Sorry Gary but that was my point,

The regs make no reference to formal qualifications in their definition of competent only technical knowledge and practical skills are enough to qualify as a competent person.............apparently.

The regs may not, but the courts will. In the event you have to defend yourself in court you would be expected to provide evidence of competence.

Training+qualifications+experience=competence

 

[fiardor]

The regs may not, but the courts will. In the event you have to defend yourself in court you would be expected to provide evidence of competence.

Training+qualifications+experience=competence

Not really the point i was making but thanks moggs LOL

 

[infinity]

we discussed this at length on here before, as my understanding was that transformerless inverters needed RCD protection, but it was pointed out that most transformerless inverters (SMA, FRONIUS etc) have inbuilt protection that meets the need for automatic disconestion that would require the need of an RCD.

do you know where we can find information as to weather SMS for example, has built in protection negating the need of an rcd for the tl range?

 

[solarsavings]

The regs may not, but the courts will. In the event you have to defend yourself in court you would be expected to provide evidence of competence.

Training+qualifications+experience=competence

Guys that have ended up in court in the past have sometime found that despite having the training, qualifications and experience they are judged as incompetent and locked up. As we see on here you can do your best, do what you believe to be right and someone will still drag the **** out of you. Get two "experts" together and it's Harry Hill time.

 

[moggy1968]

very true. Whenever 2 or more electricians are gathered together there will be an argument about the regs! (just see some of the posts on here :0) )
SO- get yourself in court with 2 'expert' witnesses and if their interpretation is different to yours your in the mire.
Your own credentials are part of your defence though. Try standing up in court and saying, 'well actually I don't have any qualifications and this was my first install' and they probably won't even need those witnesses.

 

[solarsavings]

TBH that's also true

 

[Dan]

Don't mind me while I bump some threads in the solar PV forum. If they're not current or applicable topics, just ignore the threads; they'll drop off the page. If they are, feel free to chip in and chat solar stuff in the solar panels forum.