How are temporary power, water and site services provided during construction?

Temporary services are the first thing installed and the last thing removed, and on a live site they are also the thing most likely to interfere with the operating facility.

Getting the arrangement settled before site establishment avoids a dispute about a power bill and a far more serious problem with an unsafe installation.

Where the power comes from

Two options, and the choice is made at the start.

**A temporary builder's supply** from the network, which is independent of the client's installation. Clean separation, independent metering, and a lead time for connection that has to be in the programme.

**A take-off from the client's existing supply,** which is faster and requires capacity to exist. The capacity question is real on an older school or council site, and drawing construction load from a board that is already near its limit affects the operating building rather than the site.

Where the client's supply is used, the arrangement is documented: the connection point, the maximum load, the metering, and who pays for the consumption. An undocumented take-off produces an argument at the end of the project, and the client is usually right.

The capacity assessment is the same exercise as the one in [electrical upgrades in occupied buildings](/answers/electrical-upgrades-in-occupied-buildings).

The temporary installation itself

A construction power installation is a designed installation, not an accumulation of leads.

Distribution boards with the required protection, positioned so the leads from them are short. Protective devices tested and recorded. Leads and portable equipment inspected, tested and tagged on the required interval, which on a construction site is frequent. Cable routes run overhead or protected where they cross a trafficked area.

On a live site the leads cannot cross a public or student route at ground level, which means either an overhead catenary or a protected crossing, and it is a condition rather than a preference.

Everything is re-tested through the project rather than at installation only, because a construction environment damages leads and the inspection interval exists for that reason.

Temporary lighting

Required for work outside daylight hours, for enclosed areas, and for security.

Task lighting at the work face, access lighting on the routes through the site, and emergency lighting where the work is inside a building and the permanent system has been isolated. That last item is the one most often missed: isolating a floor's lighting for a refurbishment removes the emergency lighting with it, and a temporary provision is required while the permanent system is out.

The permanent system work sits with [fire services and detection upgrades](/answers/fire-services-and-detection-upgrades).

Security lighting around the perimeter reduces both unauthorised entry and the vandalism that follows it.

Water

A metered construction supply or a take-off with a meter, with backflow prevention at the connection, because a construction water supply is a cross-connection hazard to a potable system.

The hose and standpipe arrangement cannot be left connected without protection, and the connection is certified in the same way as a permanent one.

On a site where the works affect the existing supply, the shutdown planning matters more than the temporary connection, because taking water off an operating school closes the toilets. Which means shutdowns are programmed against the operating calendar and notified, as described in [construction in live environments](/answers/construction-in-live-environments).

Amenities and waste

Site amenities need water, drainage or a pump-out arrangement, and power.

On a school or a public site the location of the amenities is a sensitivity as much as a logistics question: it sits inside the hoarded area, out of sight of the facility's users, with its own access that does not cross their routes.

Waste water from a site shed, from a concrete washout or from cutting operations cannot discharge to the stormwater system, which is an environmental compliance item covered in [environmental controls on a construction site](/answers/environmental-controls-on-a-construction-site).

Communications

Frequently overlooked and now necessary.

Site internet for the documentation, the inspection records and the photographic record, and mobile coverage for the crew. Where the site is inside a building with poor coverage, that has to be resolved rather than worked around, because an inspection record that cannot be uploaded does not exist.

Where the client's network is used, it is agreed and separated from their operating network rather than connected informally.

Removing them

Temporary services are removed, the take-off points made good, the meters read and the final consumption settled.

Any penetration made for a temporary service is sealed to the standard of the element it passes through, which on a fire-rated wall means a certified seal rather than a patch. Those closures are part of the completion inspection rather than an afterthought, and they appear in the records described in [commissioning and practical completion](/answers/commissioning-and-practical-completion).