The Clean Earth is for the Data Cabinet routers and computers in there, the supplies going to them will get connected onto one of these clean earth bars, as will the suspended floor supports (if there is a liftable metal floor) and any metal frames that form the cabinets and rack holders.....
your main earth for the UPS Unit(s) should come from the incoming main earth, this will carry on through (via the UPS)in Steel wire Armour to the supply board(or supply cabinet complete with glass door) that you are fitting inside the Data Room and bonded there...
There will be a need for an earth bonding cable from a (separate )bar there to the main clean earth (or one of them) which will be a place to bond the earth going to the underfloor sockets or feeder cables supplying the Data cabinets...
I will assume that the UPS is still a reasonable size, remember correct Battery Handling procedure for setting up and also wear safety specs and Gloves...
You will need to stock up on:
6mm Steel drill bits (eg from screwfix)
10mm Steel drill bits
25mm Holesaw x a few
32mm Holesaw x a few
20mm, 25mm and 32mm Gland kits.
Go onto ebay(best place for them) and look at the 20mm +25mm Stuffing Glands in Black and also Green (handy for doing comms rooms) you might also want to stock up on Cable ties from screwfix or ebay and look at safety electrical connection(earth) stickers, along with the standard 220V stickers, and "computer do not switch off" stickers...
If you are going into a working comms room, ask for the Fire suppression system (IG55 INOGEN) to be switched off temporarily as this could be set off by drilling/dust and is extremely expensive to refill/reset(think of up to £50,000 depending on the system size)as well as possibly dangerous if you are in there when it goes, especially if it is a room wide high-pressure system...which a lot are in Data centres
Small Data rooms in low load facilities (private offices etc) are usually only cabinet interior low pressure/low volume systems...which are usually quite safe...
I think that there is quite a high chance that they will refuse to switch this system off, either because it would involve turning off the whole building/facility, or more likely they will not know how to.....
A way to get around this as a last resort is to get a gas spanner and carefully disconnect the pony firing bottle hose from the cylinder chain, this will disable the fire system in that room only .....best bet is to ask them to get their maintenance people to do it for you...this will stop the Gas suppression system from emptying if work accidentally sets off the fire alarm..
Another thing to remember is to watch out for any underfloor water sensor pads/straps and the connection wires, as if you stand on one it will cut off the coolant pumps to any floor standing air conditioning/cooling units and close the valves as well, this is incase of leaks...these are usually situated about the concrete floor next to cooling water pipes that come in from the plant room...will save you needing to get into the plant room to turn back on again...