central battery unit

[novernmunkee]

hi guys can anyone help with this one
i have being given the task of maintaining emergency lighting to a large office complex.
the emergency lighting is fed of a ac/ac 230v central battery unit.
under normal conditions 230v flows through the cbu and out to the lighting, under fault condition i.e loss of 230v a bank of dc 110v batteries kick in which is then inverted 110v dc to 230v ac for a specified time
the problem i have is that how do i safely isolate the 110v dc batteries as i need to change them as they are on there way out
any suggestions greatly received and appreciated thanks neil

 

[Knobhead]

Have a look at

http://www.sonnenschein.org/PDF files/BatteryRoomVentilationInstallation.PDF

I’ll be honest I hate working on large battery systems. If I have to then I split the banks in to small units of say 30V each.

One thing to bear in mind is why they are there. You can’t start messing about with critical systems without forward planning.
I’ll quote an engineering manager “swap over to the new battery bank while the plants are running”. My reply would soon get censured by Marvo! I did the change over at midnight on a Sunday when I could safely shut down the 40MVA 11KV board. Any fault while I was doing the change over wouldn’t clear until the batteries were reconnected.

 

[Marvo]

My reply would soon get censured by Marvo!

You're probably right, I would also have had a few choice words

Large battery installations were a part of my apprenticeship but I still avoid them like the plague. It's just an environment I don't work in very often and I'm not that comfortable in. I also know how dangerous they can be.

 

[Engineer54]

Just read this PDF file, and while i can agree with most of what's been written/stated, i can't reconcile the statement about ''Must Not be Ex protected'' Every battery room installation i've been involved with has been fitted with Ex lighting fittings and lighting switches (where switches were located in the room). All conduit and fittings were PVC covered heavy gauge apart from the light fittings and switches, and with sealing adaptors . Main Battery isolator was again Ex, and mounted on insulated metal floor bolted frame. Battery racks were positioned in the centre of the room to allow free air flow through the battery rack

The room walls were tiled using epoxy grout, the ceilings and floors were sealed and coated with an epoxy paint!! No ventilation fans permitted to be located within the rooms boundary, eg ducted supply and extract!! Extract ducting incorporating gas detection sensor and optical smoky... Rooms had halon gas (and now halon replacement) mass discharge suppression system.

So as you see, a bit different to what has been stated in this PDF file. All i can think of, is that our specification(s) are based on a standard(s) other than the EN 50272-2, referred to in this file data??? Can't help thinking that, not all information was being being given in the file either....



http://www.sonnenschein.org/PDF file...stallation.PDF

 

[Knobhead]

To be honest E54 I’ve never done a battery room install, but I’ve inherited them as existing. I don’t think I’ve ever seen two similar set ups. Some I will say were death traps but the companies were unwilling to spend anything, the usual “it’s been like that for the last XX years”. Give up it’s the less painful option unfortunately became the norm.