DC Switch Disconnector for PV system

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TPower
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DC Switch Disconnector for PV system

Post by TPower »

I’ve been doing inspections on two PV installs, and I have had a bit of difference of opinion with the electrician and his supplier regarding the DC switch-disconnector that is required to be located at the inverter.

Currently there is no separate DC switch-disconnector located at the inverter, only the one that is integrated into the inverter itself. I’ve advised them this would need to comply with 5033/2012:4.4.1.2 (b) in order for a separate switch-disconnector to be absent, and it doesn’t appear to meet this requirement. So I’ve advised they need to install one as per 4.4.1.2 (a).

I’ve been presented with a manufacturers written statement for Australia, advising the inverter complies with 5033/2014:4.4.1.2 (c) and... ‘Due to the above compliance, an adjacent and physically separate load break disconnector is not required in the installation’.

My understanding is this statement is somewhat irrelevant, as it’s for Australia and mentions the 2014 standard, so shouldn’t be relied on in NZ, where the 2012 version is law. The description in 5033/2014:4.4.1.2(c) isn’t even mentioned in the 2012 standard. Therefore a separate DC switch-disconnector should be installed, to comply with the 2012 version. Does this sound right? Am I missing something here? I’ve been told, ‘these units have been installed throughout NZ and it hasn’t been raised as an issue in the past, and that the 2014 standard is the superior one that is recommended and used in NZ by an organisation called SEANZ’.

There’s some resistance to accept what I’m saying is correct so perhaps I’m missing something? In short, can we rely on 5033:2014 in NZ for installation and inspection?

Any advice much appreciated! Thanks

https://www.sungrowpower.com/sites/defa ... %201_0.pdf
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DC-SWITCH-DISCONNECTORS DECLARATION for Australia.pdf
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JamieP
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Re: DC Switch Disconnector for PV system

Post by JamieP »

You sound more correct. 2014 may be a better document but as you say, it's not cited by regulations so it's the 2012 one we must go by. 2014 may have better information to go from and may be used as a "best practice" but only if any of it's requirements don't directly conflict with the 2012 cited document.

2012 gives 2 options of compliance, so if it doesn't meet (b) then it must meet (a) and if it meets neither then it's non-compliant
JamieP
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Re: DC Switch Disconnector for PV system

Post by JamieP »

Just had a better look over things and compared the standards and also looked at the declaration, 2012 doesn't have option C that the inverter complies with so it definitely needs an external DC switch-disconnector in compliance with 4.4.1.2 (a) until we finally cited 2014 in regulation
TPower
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Re: DC Switch Disconnector for PV system

Post by TPower »

Thanks for the feedback. Yes that was my thoughts too. I have seen some units in the past that comply with 4.4.1.2(b), Fronius Inverters for example. The switch-disconnector is built into the base of the unit that stays fixed to the wall, allowing you to isolate and remove the entire inverter.

One other non compliance I found with one of the installs was no circuit protection installed between the inverter and a compatible storage battery. The electrician had just installed an isolator. I checked the MI and it had a note indicating... ‘A two-pole DC circuit breaker with over-voltage and over-current protection (100 V DC and 100 A DC) should be installed between the SH series hybrid inverter and the battery’

Since pointing this out, the electrician has now installed HRC fuses in lieu of a DC circuit breaker. I still don’t think this is correct, and believe a circuit breaker should be installed as per MI? I’m struggling to find the clause to back this up. There’s information in 5033/2012:3.3.3 advising that overcurrent protection shall be provided for batteries, but I thought there might be a more overarching clause advising the need to install as per MI.

I’m not entirely sure if the storage battery is inspectable, it’s associated equipment so I’m guessing so. Either way, it still needs to be compliant.

https://www.sungrowpower.com/sites/defa ... pdf#page43
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