5033 Switched Disconnector at PCE

[Slovett]

Hi,

Just a question about Array Switch Disconnector adjacent to the PCE.

I can't find the answer in either 5033:2012 or 5033:2021 (yet).

When connecting 2 arrays at the PCE (Each array will be connected to a separate MPPT input) is it acceptable to use 1x 4 pole Switch Disconnector, or do you have to use 2x 2pole switch disconnectors? Each array will be at a different voltage - ie. Array 1 @ 300VDC & Array 2 @ 200VDC - Im guessing 2 seperate SD reduces the risk of internal arcing between switch contacts.

[PeteRig]

I think it comes down to if the contacts of the DC Switch Disconnect can handle the current (rated operational current v rated operational voltage ) of each array using only two poles, the data sheet for the disconnect will confirm this.
Generally I see 4 poles used in series for each array, so two disconnects but if the inverter as a built in DC Switch Disconnect (as most do) and meets the requirements of 5033 clause 4.4.1.2 that's only one switch.
For the cost of the switches I cant see why installers wouldn't use a separate switch for each array as well as the inbuilt switch, if there is an issue with one array at least you can isolate that and keep the system going.

[AlecK]

Agree separate devices for each array is preferable.
Just good design.

[JamieP]

Also a question I've wondered.
Know that each MPPT connection is deemed a separate array and that each array requires one.

Question is is one device for two arrays suitable as you're asking and I don't have a definitive answer.

I advise clients for one for each array as I'd rather be on the safe side but it can be difficult to argue or not pass an RoI without a definite reference.

[PeteRig]

Hi Jamie, if you refer to the figures at the start of 5033, it clearly shows configuration for switch disconnects, that should help

[JamieP]

What about 2.1.4.2?

"Each PV array shall have a switch-disconnector to provide isolation of the inverter. The provisions of multiple switch-disconnectors in
Clause 4.4.1.3 applies and a warning sign as required in Clause 5.5.2 shall be provided."

Or does having a shared one still consitute each array having one?

[PeteRig]

Sorry Jamie I am away at present so don’t have any references with me, but just off my head sharing is not the same as individual switches obviously
I still think as I mentioned above individual switches give the option of isolating an array if required, greater switching capabilities with the number of poles if they are limited eg can use 4 poles per array instead of 2

[AlecK]

If it doesn't say "individual" or 'separate" then those concepts are not mandated.
Equally "shall have a" doesn't mean a common device can't be used.