Making off in main switch

[edrobbo8]

Hi guys,

Have to make off some 95mm lugs onto an old Bill main switch, which has 160A fuses. There are 4 terminals with an M10 dome head bolt with a square shank for the 3 phases and neutral, and there are currently 2 lugs on each bolt, 1 feeding a main dis board and 1 feeding a new switch fuse that goes to a seperate control room.

We need to get a third 95mm lug on to each terminal, would it be acceptable to put two lugs on each bolt secured by a nut, then our 3rd lug onto the bolt which will sit tight up to the 1st nut, and tightened up with another nut? Hope that makes sense!

 

[TNS]

No, use a tinned copper spacer between the 2[SUP]nd[/SUP] and 3[SUP]rd[/SUP] lugs. One nut then tightens the full assembly evenly.

I’ve got to ask but why are you doing this? It’s bad practice to have a switch feeding more than one supply!

 

[Engineer54]

No, use a tinned copper spacer between the 2[SUP]nd[/SUP] and 3[SUP]rd[/SUP] lugs. One nut then tightens the full assembly evenly.

I’ve got to ask but why are you doing this? It’s bad practice to have a switch feeding more than one supply!

Not best practice i agree, but no different than a main switch feeding a bus bar which in turn supplies 3 further switches...

 

[edrobbo8]

Thanks for the advice. The main switch supplies one dis board, and they are building a new shed and due to the increase in load for the generator, the new building has a separate generator as back up. Our system is PV so has to bypass the generator so cannot go into the existing dis board.

 

[Engineer54]

Thanks for the advice. The main switch supplies one dis board, and they are building a new shed and due to the increase in load for the generator, the new building has a separate generator as back up. Our system is PV so has to bypass the generator so cannot go into the existing dis board.

Best practice here calls for a small Bus Bar chamber before the DB. That can then be the means of connecting the DB, the new supply to the new building and your PV system. All via there own CBs...

 

[mogga]

I was going to say same as Engineer there

 

[Knobhead]

What length of cable are we talking about? Sorry I wouldn’t be happy with a set up like this at all. I’m going with E54 on this a bus-bar chamber with individual protection for each of the feeds would be way to go.

It would future proof for any further expansion.