Difference between revisions of "Power/Estimates"
m (AlisonW moved page 447 Hackney Road/Power/Estimates to Power/Estimates: We're now here, so drop the superfluous bit (and use of sub-pages))
Revision as of 23:24, 9 May 2013
With the move to 447 Hackney Road comes the substantial revision of how the premises are used and the requirement for additional electrical circuits to meet the needs of the Hackspace.
Power at 447 splits into four tasks:
- Local Distribution Boxes (LDBs aka 'Consumer Units'): to bring the fusing closer to the usage and remove the need to access the landlord's main intake room.
- Cables: to connect the main intake room and the LDBs
- Area circuits: connections to equipment and outlets from each LDB
- Replacement of the existing main fuseboxes in the main intake room with modern replacements using MCBs in place of fusewire
Because I have been thinking in terms of these four tasks and discussing them separately it is possible the case that I may have misled people over the total cost (as opposed to cost per task). I shall try to provide more detail below:
Local Distribution Boxes
The plans and notes at 447 Hackney Road/Power detail these. Prices for CUs are competitive from the big warehouses as well as trade and specialist suppliers so it will be worth looking at what deals may be available.
At present we need CUs in 7,9,10,12, and 16 module minimum sizes. It may be better to standardise and get a bulk discount or buy the best offer, eg. Wickes 17th Edition Fully Loaded Consumer Unit is currently £47.99 inc vat. and would give a total cost of about £250.00.
We will need additional heavy-capacity cable to each all LDBs above what is present on the reel I supplied. Estimated minimum run lengths are as follows:
- LDB A: 16m rated 90A (16mm csa)
- LDB B: 21m rated 90A
- LDB C: 32m rated 60A (10mm csa)
- LDB D: 10m rated 90A
- LDB E: extant
- LDB F:12m rated 90A
- LDB J: 5m rated 60A
- LDB K: 17m rated 90A, or 22m if extra room is built
- LDB L:30m rated 60A
This totals 76m of 90A-rated cable and 67m of 60A-rated. I believe my reel has approx 35m of the former left on it (tbc) reducing the 90A-rated requirement to approx 40m. These cables come on 50m reels. Cable glands should normally be used when these cables enter boxes or equipment. Cleats will be required for affixing to walls.
Depending upon whether the Hackspace is classified as 'public' or not we might need to use LS0H cable (LS0H SWA Cable is used in public areas because the sheath only emits very low levels of smoke and non-toxic levels of halogen gas when exposed to fire; usually under 0.5% HCl emission).
I'm still trying to locate cheaper suppliers, but as a guideline TLC charge as follows:
- 10mm x 3core: 50m drum @ £206.50+vat 100m drum @ £390.00+vat (or £4.54+vat per metre)
- 16mm x 3core: 50m drum @ £277.00+vat (or £5.90+vat per metre)
A total estimate for additional feeder cables therefore is around £700 inc vat.
We have plenty of t+e cable in various ratings so should not need to purchase any more. We will however need to put some of these in conduit. Exact requirements will not be known until things are in place except for the server outlets and biolab. The new classroom has already been fitted with sockets under another budget. The total requirement so far is:
- 2x 240V 16A single-phase CEEform outlets (around £6 ea)
- 17x switched double sockets, either metal-clad (around £12 ea) or white with surface patresses (around £6 ea) but probably a mix depending upon area use.
but this will clearly increase as the ground floor area usages demand particular services.
Replacement main fuse boxes
My - possibly misguided - initial thought here had been that we could keep the two present boxes in place and just replace the internals with DINrail-mounted MCBs. I've since realised that is probably a non-starter unless we can cut a plastic guard sheet to suit (for safety) and that replacement will probably be required. The supplier I used to use for these is no longer in business and I'm having trouble finding alternatives. One appears to be Hager uk with a relevant [range but (amazingly) the link to their price list 404s. I'm going to keep looking. Whereas I knew the price brackets in the past I haven't done a warehouse/conversion in a long while so don't know what the price is likely to be now. I would welcome assistance.
The current fuse boxes (large three-phase, small single phase) show 24 fuse slots in total, and we need to add (at least) a further 9 circuits. The space available to fit new boxes is fixed to that of the current space as we need to maintain the termination locations for the existing cables.
Current plans show a total of eight maintained emergency exit lights. Example Robus 3 Hour Emergency Lighting Exit Sign at screwfix at £40.09ea inc vat. Total for eight is £320.72 but other suppliers should have bulk discounts available.
- Local Distribution Boxes:£250
- Cables: est £700
- Area Circuits: est £360
- Replacement main fuse boxes: see above
- Emergency exit lights: £321
- Total: £1,631 plus replacement main fuse boxes.