As far as the install goes there is no need for a RCD
- Thread starter yellowvanman
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This thread titled "PV on shared RCD" is posted in the under the Solar PV Forum | Solar Panels Forum on Electricians Forums.
Type B RCD requirement relates to DC seperation.
If by design the inverter can't leak DC then Type B not needed. Usually that means glavanic seperation, i.e. transformer. Some transformless inverters have specific built in monitors to stop / manage dc leakage and hence remove the requirement for a Type B RCD, this can effecteievly only be done if specifically stated by the manufacturer. I know that SMA nd Power-One both make that statement, and from reading the above, presume that Fronius have also done.
HOWEVER, sometimes they say that if it needs to be protected then it should be on it's own dedicated RCD and often that is 100mA per inverter.
Manufacrurers guidelines overide the DTi Guide, howver it's like the good old 16th / 17th edition discussion - what was the requirement WHEN IT WAS INSTALLED...
Best practice dictates that if it requires an RCD it should be dedicated to the Inverter, then if 100mA required, other circuits are not put at risk.
Our practice is to design out the requirement for an RCD whever we can.
For the full 9 yards just search this forum there's one thread that I think goes on for about 10 pages about it.
If by design the inverter can't leak DC then Type B not needed. Usually that means glavanic seperation, i.e. transformer. Some transformless inverters have specific built in monitors to stop / manage dc leakage and hence remove the requirement for a Type B RCD, this can effecteievly only be done if specifically stated by the manufacturer. I know that SMA nd Power-One both make that statement, and from reading the above, presume that Fronius have also done.
HOWEVER, sometimes they say that if it needs to be protected then it should be on it's own dedicated RCD and often that is 100mA per inverter.
Manufacrurers guidelines overide the DTi Guide, howver it's like the good old 16th / 17th edition discussion - what was the requirement WHEN IT WAS INSTALLED...
Best practice dictates that if it requires an RCD it should be dedicated to the Inverter, then if 100mA required, other circuits are not put at risk.
Our practice is to design out the requirement for an RCD whever we can.
For the full 9 yards just search this forum there's one thread that I think goes on for about 10 pages about it.
All good advice, to a degree....best practice - as stated - try to mitigate the requirement for an RCD in the first place. If this is not possible, then provide a dedicated RCD for the inverter. I wont even go into the differences between "nuisance tripping" and DC-sensitivity/leakage-currents (there's lots of historical threads on here where we've bashed this subject about ad nauseum...) ;-)
Fascinating that the inverter manufacturer's statements on whether, by design, they could inject DC onto the AC circuit should dictate what type of RCD you install......is the inverter manufacturer responsible/liable for the design/installation of the complete PV installation? Equally fascinating that the DTI Guide seems to have been tailored/modified to "accommodate" those statements issued by various TL inverter manufacturers for the UK market. Also, still a lot of confusion over the reason/purpose/function of an in-built RCMU (residual current monitoring unit) which doesn't really help things....have a read here for a recent article issued by Doepke UK on this Electrical Products - Solar Inverters incorporating RCM units - Why do you need an RCD as well?
Fascinating that the inverter manufacturer's statements on whether, by design, they could inject DC onto the AC circuit should dictate what type of RCD you install......is the inverter manufacturer responsible/liable for the design/installation of the complete PV installation? Equally fascinating that the DTI Guide seems to have been tailored/modified to "accommodate" those statements issued by various TL inverter manufacturers for the UK market. Also, still a lot of confusion over the reason/purpose/function of an in-built RCMU (residual current monitoring unit) which doesn't really help things....have a read here for a recent article issued by Doepke UK on this Electrical Products - Solar Inverters incorporating RCM units - Why do you need an RCD as well?
Reply to the thread, titled "PV on shared RCD" which is posted in the under the Solar PV Forum | Solar Panels Forum on Electricians Forums.
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