I am curious if you may install the changeover switch in a sub db close to the inverter, or if it must be in the main db?  The main db is old, and very restricted in space - just trying to see if I can save some money here...  The question really is - what must be installed in the main db, and what can be moved into a sub db that is say in the garage?

You ^can^ install it in either DB, but SANS regulations stipulate that an isolator needs to be close to the unit being isolated. So if you use a mechanical change over switch as isolator, it should be close to the inverter. This way, when you work on the inverter someone in the house can't accidentally change over (hypothetically speaking) and kill you. 

If you want to install it in the house and matter of convenience, then you also need an isolator at the invertor - same as your geyser has an isolator at the DB, and one in the roof. 

And you install a double pole isolator on the input of your inverter as well. 

Ok, perhaps I should have been clearer about *which* change-over switch I was referring to - this is the one on the output of the inverter, that has three positions:

• Essential loads connected to Eskom
• Disconnected from both Eskom and inverter
• Essential loads connected to inverter

There will also be an isolator on the input side to the inverter - for disconnecting it from the grid.

I am not sure how the change-over switch I referred to above can hurt you if someone switched it in the house?  Just curious, really - I don't want it in the board in the house as there is no space left there.

8 minutes ago, admiral said:

Ok, perhaps I should have been clearer about *which* change-over switch I was referring to - this is the one on the output of the inverter, that has three positions:

• Essential loads connected to Eskom
• Disconnected from both Eskom and inverter
• Essential loads connected to inverter

There will also be an isolator on the input side to the inverter - for disconnecting it from the grid.

I am not sure how the change-over switch I referred to above can hurt you if someone switched it in the house?  Just curious, really - I don't want it in the board in the house as there is no space left there.

I am sure we're talking about the same unit You can either use a rotary one, like on the generators, or a DB mounted one. As long as it has a center-off position. I like the Hager DB mounted ones as below:

 

 

 

This is the same argument I've had with the regulation for years. If your garage motor is further away than 2m from the DB board, it needs an isolator. It's regulation. Even if you argue as much as you like that "I am on the only one living here and no one can accidentally turn it on", regulation states you either need to have an isolator at the gate, or a lockable isolator in the DB board. There is a clause that if it's in line of sight, the isolator isn't necessary. 

I bring this up as I often see sparkies charging people unnecessary to "fix" this. 

An isolator in the roof for the geyser is a different story though since is't never in light of sight. 

I have a similar question with regards a change over switch . I have a grid tie PV inverter normally running on the grid however when grid fails I want to change it to run on my Victron output in "AC coupled " mode.  Now the grid connected stuff is on DB board 1 and the Victron powered stuff on another DB board 2.  I therefore have to provide a feed from DB2 to DB1 to a change over switch which will be mounted in DB1 .  Do I have to provide an isolator in DB1 ( at the point of entry  for the alternate supply before the change over switch ?  Similarly  do I have to provide an isolator in DB2 at the interface to the feed from the grid tie inverter in DB1 ?  Is a 2 pole MCB ( 1P+N ) considered an isolator?