Site Survey & Grid Application

Explore each method in depth - benefits, limitations, plant and quality control on its own page.

Site Survey & Grid Application: step by step

1. 1

   Step 1: Establish what the client wants the site to do

   Before anybody surveys anything, the brief gets pinned down in terms of demand rather than equipment. How many vehicles, arriving when, staying how long, and needing how much energy while they are there. A motorway forecourt where drivers stay twenty minutes is a completely different electrical problem from a supermarket car park where they stay an hour, and both are different again from a depot where the whole fleet plugs in at seven in the evening and has to be full by five in the morning. That profile decides the power per bay, the number of bays and whether the peak can be managed rather than bought. It is also the number that goes on the connection application, so it needs to be right first time - changing the requested capacity later usually means going back to the start of the queue.

2. 2

   Step 2: Survey the site above and below ground

   A full topographical survey is taken and referenced to a site coordinate grid, along with a utility survey of everything buried between the likely supply position and the likely bays. Existing records are collected from every asset owner who has plant in the area, then treated as a starting point rather than as fact, because buried plant records are routinely incomplete and rarely accurate about depth. Detection equipment is used across the whole route and trial holes are dug at the crossings that matter, so the awkward services are found on a quiet afternoon rather than by an excavator on a live forecourt. Levels, falls, drainage, surfacing construction, structures, tree roots and anything the route has to pass under or around are all recorded while the surveyor is there.

3. 3

   Step 3: Establish the existing supply position and measure the real demand

   The incoming supply, its metering arrangement, its capacity and its physical position are established and photographed, and the existing electrical infrastructure is assessed for its condition and its spare ways. Then the site is monitored: loggers are put on the existing supply for long enough to capture a genuine peak, including the seasons and the trading patterns that matter, because the difference between the agreed capacity and what the site actually uses is the free headroom the scheme can have. Estimating that number from the meter rating is how projects end up applying for capacity they did not need or, worse, designing a scheme that trips the site's main supply on the first busy Saturday. Measured data also carries far more weight in the conversation with the network operator than an assertion does.

4. 4

   Step 4: Test the layout on paper before committing to it

   Bays, units, plant positions and cable routes are laid out and then tested against how the site is actually used. Swept paths are checked for the vehicles that will use the bays and for the delivery vehicles that will not - a bay that a car can reach only by a three-point turn will sit empty. Accessible bays, pedestrian routes, cable reach, door swings, screen visibility against the sun, canopy heights and the position of anything a reversing vehicle can hit all get worked through now. The plant compound is placed where a lorry can reach it for the eventual replacement of the equipment inside it. Every metre saved between the supply position and the bays is a metre of trench that does not need digging through a trading car park, so the routing is worth arguing over at this stage.

5. 5

   Step 5: Make the connection application and read the offer properly

   The application goes to the distribution network operator with the demand profile, the proposed capacity, the site plan and whatever supporting information it requires, submitted as early as the brief allows because the clock starts on receipt rather than on completion of the design. When the offer comes back it is read in full and not just at the price. The capacity offered, the point of connection, the arrangement expected, the works the operator will carry out, the works the client is expected to build, the metering requirements, the acceptance period, the payment stages, any reinforcement conditions and the delivery date all shape the project from that moment on. Accepting an offer without working through its conditions is one of the most expensive mistakes available on a charging scheme, because the conditions are contractual and the date is real.

6. 6

   Step 6: Work the options where the capacity is short or the cost is prohibitive

   When the offer does not work, the design changes rather than the ambition. Reducing the power per unit while keeping the bay count usually costs less revenue than it saves in connection charges. Active load management lets a modest connection serve a busy site by sharing what is available between the vehicles plugged in. Staging the scheme lets the first phase trade while the network reinforcement is delivered for the second. On-site storage or generation can carry a short peak that the connection cannot. Another position on the site, or the other side of a boundary, can land on a different part of the network entirely and price completely differently. Each option is put back to the operator and the client's operator as a proper alternative, and the comparison is made on whole-life cost rather than on the connection charge alone.

7. 7

   Step 7: Secure the land, planning, consents and permits

   The route and the plant positions need rights as well as space. Leases, licences, wayleaves and easements are established for the cable route, the plant compound and the bays themselves, including anything crossing land the client does not control, because a route agreed verbally with a neighbour is not a route. Planning is confirmed for the units, the plant enclosures, the canopies, the signage and the lighting, and the conditions attached to it are listed and owned. Permits for working in or near the public highway, for traffic management and for any excavation in adopted surfacing are identified with their own lead times. On a leased site the landlord's consent is its own process and frequently the slowest of the lot.

8. 8

   Step 8: Fix the design and build the programme backwards from energisation

   With the offer accepted and the consents in hand, the design is frozen and issued, and the programme is built backwards from the date the network operator will energise rather than forwards from the date the contractor can start. Long-lead items are ordered against that date, and on these schemes that means the units themselves, the switchgear and anything the operator has to manufacture. The phasing plan for the live site is drafted at the same time, because the number of bays the client will release at once is a constraint on the civils and needs agreeing before anything is priced as continuous work. Assumptions carried through the feasibility are written down in one place so that when one of them moves, everybody can see what else moves with it.

How long does Site Survey & Grid Application take?

Typical duration: The survey and feasibility work typically takes 4-8 weeks, but the connection enquiry, offer and delivery process runs for many months and on a constrained network can take longer than the rest of the project put together..

Related processes

• Civils & Groundworks
• Electrical Infrastructure
• Charger Installation
• Commissioning & Energisation
• Connection using spare capacity in the existing supply - method
• A new or upgraded network connection - method
• A capacity-limited scheme with active load management - method
• Connection supported by on-site storage or generation - method
• EV Charging Infrastructure sector guide
• Utilities & Energy - group of sectors