UPS Install

[James Sutton]

Hi All

I was asked to run a new supply in a comms room for a small IT service 1x 32A commando socket. When i gained access to the comms room today to look at what i thought would be a straight forward job. It was a 8kVA ups sitting there not a small comms rack. The data on the UPS states taht a 100A input. The data sheet requires a 50Amp 16mm from manufactures data.

The only way this would be possible would be to isolate the rising busbar and install a tap off box to supply the UPS. The run from the riser to the comms room is around 30 to 35 metres. The only route would be under the floor void so i will be installing cable tray under the floor for the cable to run on.

Ive never really got involved with the installations of UPS systems i know 8kVA is small to some of the other system i workwith but as i said ive never got involved with the install of UPS system.

Also ive seen alot of UPS install carried out in Buetal instaed of SWA. What would be the best type of cable to use onthis install Any advice would be grateful

Thanks

James

 

[Brightspark2]

We usually use SWA on tray under the floor void like you say, although this isnt really choice but specification....

 

[bugsy]

new busbar tap off , 16 mm SWA on basket / slab ( maintaining segregation from IT runs ) , Isolator in comms room,
You may also want to run clean earth and install clean earth bar with disconnecting link

 

[grantr37]

you can run SWA under the floor then fit a 63A MK Blue (220V) underfloor commando socket box, then drill out a hole in the metal suspended floor and fit in one of those nifty cable entry letterbox thingies that has bristles around it a bit like a draught excluder, the 63A socket box secures onto the floor, and the SWA may be fastened onto the floor using suitable saddles/p clips, or better still run along 75mm basket raised up off the concrete floor using UNI Strut cut into 100mm lengths with palstic end caps on it and a bit of Galvi paint....


there's socket boxes with RCBO's built in, but I imagine that they will want a small Garage style box fitted on the wall about waist height beside where the rack is with the supply to the underfloor socket going through the SWA via a combination of 25mm metal conduit and COPEX.....as they won't want to be lifting floor tiles......an in line commando plug and socket between the UPS and the floor plug will also probably be of interest to them to let them easily swap out the UPS unit without lifting tiles.... or an inlet socket that accepts a commando socket as a power input( commando socket pushes onto it ) secured onto the cabinet/rack....




63A commando underfloor socket box - about £65.00

63A commando underfloor socket box with RCBO- about £140.00

63A plug - about £25.00

extra plug and socket (in line) to do change over of equipment by the user - about £50 for the two

Wall mount RCBO in single box- about £35.00 all in....


would generally say that if this is a suspended floor (lift out tiles) then they will probably want the power supply to come from underneath the UPS to inside the cabinet/rack and be hidden, so the option of using an underfloor socket would be best, with a wall mounted easily accessible isolator/breaker....

 

[grantr37]

forgot to say, there will already be a clean earth bonding bar in the room somewhere nearby,in fact there might be 3 or 4 probably on the wall in plain view, and all the support pillars of the suspended floor will most likely be earthed individually (IT installers earth every single one) I have done a large site a while ago with about 900 underfloor supports and they spent 3 weeks earth bonding each and every one of them....
you can run a 10mm earth and bond it onto one of the clean earth bars already there, this should be bonded onto the case/frame for functional earth/ noise cancellation.....the supply earth should be bonded as normal back to the board....


your clean earth bars will be connected to a point in the switch room/plant room that goes off outside to a separate earth farm...

 

[bugsy]

your telling me you connected floor pedistals to the clean earth bar! -------------- your nuts

 

[grantr37]

your telling me you connected floor pedistals to the clean earth bar! -------------- your nuts

They had their own separate clean earth Bars and were interlinked in lines/rows about 45 long by 30 rows wide,10 rows to a Bar, 3 earth Bars... and that was part of the design from the Network Rail Engineers, there were then several independent clean earth points throughout the building for IT equipment, this was a Data Centre.
I did not fit them, 3 sparks mates/labourers got tasked with this after the flooring company had finished.