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DNO Renewables

When do I need a technical site survey?

How a site survey helps a DNO application, and when it's worth booking one before applying.

Written by the DNO Renewables teamUpdated

A technical site survey is an on-site visit by a qualified surveyor who inspects the incoming supply, existing installation and the space where the new system will go. The output is a report with photographs, measurements and technical observations.

When it's worth booking one

  • You can't get the customer to send you accurate information. A survey solves that in one visit.
  • The supply configuration is unusual. Three-phase / single-phase mismatches, historic wiring, or commercial supplies with unclear cut-outs.
  • The site is being scoped for solar, battery, EV and/or heat pump together. A single survey can cover all technologies.
  • You want a clean, DNO-ready pack. Cut-out photos, MPAN, wiring diagram, load information — all in one report.
  • The project is commercial and the customer expects a professional survey document as part of the proposal.

When it's not necessary

  • Standard domestic G98 on a straightforward supply where you've already visited or have the required photos.
  • Repeat installer who knows the site type well.

What the surveyor does on site

  • Inspects the incoming cut-out, meter and tails.
  • Photographs the fuse rating and supply arrangement.
  • Measures the space for the proposed equipment (inverter, battery, consumer unit).
  • Notes any existing generation or heat pumps.
  • Confirms the MPAN and cross-checks it against the physical supply.

Turnaround

A report is usually returned within a few working days of the survey, depending on scheduling. You can then use it directly to submit the DNO application.

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