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Author Topic: PV Installation Guidelines  (Read 50961 times)
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« Reply #30 on: December 02, 2016, 12:34:27 PM »

Ted, does that mean a SMA4000TL does not need one ?

As it has a pull down isolator dongle thing.

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« Reply #31 on: December 02, 2016, 01:33:47 PM »

The switch on a SE inverter is a small toggle switch or press button. Through electronics / relays it effectively performs the same function as a standalone separate switch disconnector.  So the lack of a separate switch does not add much safety risk.

However, the MCS process is very rules based and I would expect to be picked up if seen missing by an MCS Assessor. Have a look at the rules linked to earlier in this thread.  Para 2.1.12 et seq.

My interpretation is you should have one if a MCS system. Very useful for testing anyway. I did stop installing PV over a year ago so someone might be along with a more recent view.

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« Reply #32 on: December 02, 2016, 03:24:00 PM »

If the switch on the inverter isolates the DC input then you don't need a separate switch. What model of inverter do you have?

The inverter is a Trannergy which does have an isolation switch. The panels feed into is an Growatt Sp2000 which also has an isolation switch. So it would seem the original installers were right in saying one is not compulsory.
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« Reply #33 on: December 02, 2016, 04:47:34 PM »

The use of a separate dc isolator is common sense and good practice regardless of what the rules may permit and whether the inverter has an isolator or not. The latter is OK at first install when the installer can make final connection to the panels on up the roof after wiring to the inverter.
But consider the situation where the inverter fails (after install) and someone needs to replace it...
They are then faced with having to disconnect 'live dc tails' from the inverter OR go up on the roof with the applicable H&S requirements to isolate the end feeds from above - or do it at night of course  Roll Eyes


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