UPS connection common neutral supply & load

[howsitgoing]

Hi

Maybe im over thinking this but need to connect a UPS system to a control panel, the problem is the ccts i want to connect to the UPS are split & all the neutrals are all connected to a single busbar connection unit at the moment which is all normal, but i need to connect a UPS to power supply to 50% off the ccts (PLC ccts only) so can i common up the UPS supply side & Neutral side of this UPS back to the existing busbar connection unit or do i have to split the neutrals & connect them all to the load side only of the UPS.

cheers
baz

 

[Darkwood]

Welcome to the forum

 

[Pete999]

What sort of loading are you trying to keep energised? how big KVA is the UPs you intend to use?
You may have consider having some sort of load shedding arrangements installed, so as in the event of the power outage only the essential loads are kept going.

 

[davesparks]

I'm not sure I've entirely followed your post.
But I think what you want to know is that multiple circuits fed via a ups would need the ups to be upstream of the distribution board which feeds the circuits. Or in other words you would have a distribution board after the ups which feeds these circuits.

 

[Brightspark2]

The neutrals for the circuits you are supplying need to be connected back to the UPS separately. So you would need to split them from the none UPS neutral bar.

 

[Pete999]

It's difficult to help when more information is required, I asked you for info in post 3

 

[kingeri]

It always amazes me when somebody posts asking for help then doesn't respond to their own thread.

 

[Pete999]

It always amazes me when somebody posts asking for help then doesn't respond to their own thread.

Yep annoying isn't it?

 

[Lucien Nunes]

Generally you must not connect supply and load together, because of the increased risk of the supply being back-fed if a fault occurs on the load side. You would have to provide a separate neutral bar for the circuits being moved over to the load side of the UPS.

 

[Pete999]

Generally you must not connect supply and load together, because of the increased risk of the supply being back-fed if a fault occurs on the load side. You would have to provide a separate neutral bar for the circuits being moved over to the load side of the UPS.

Lucien, would the best option be to use two Distribution boards, one with the essential circuits, and one for the non essential circuits?

Take a feed from the raw mains, and a feed fom the output of the UPs have two outputs 1 essential and 1 non essential inputs and outputs through a suitably sized contactor 2 NO and 2 NC sets of contacts the control circuit could be either fed fro the raw mains or the UPs output, just depends on how the ins and outs are configured in the contactor, I tried to get sizes and load information from the original poster but he has either lost interest, or been busy working and has no contact with the forum.

 

[Lucien Nunes]

Possibly, although the way I read it the essential circuits are PLC power supplies built into a panel and that they weren't fed from a DB as such. If their OPD is in the panel too then it's just a question of segregating the neutrals but as you say it might be best to run them out to a new DB.

 

[howsitgoing]

Hi Guys

Very sorry for not replying must be my forum settings are not set correctly yet for receiving notification, many thanks for the reply's & yes it is a huge chiller control panel that was engineered in case of failures by even splitting the Neutrals on the same CCT instead of daisy chaining them, yes you have confirmed for me I am going to have separate the ccts on the PLC cct i wish to protect & install another Neutral block on the load side of the UPS.

thanks
baz