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DNO Renewables
Documents1 min read

What is an SLD and do I need one?

The Single Line Diagram shows how the system is wired. Every G99 application needs one.

Written by the DNO Renewables teamUpdated

What it is

A Single Line Diagram (SLD) is a simplified schematic showing:

  • The grid supply point
  • The customer's consumer unit
  • Every inverter, battery, EV charger, or heat pump you're installing
  • Where the meter and export CT clamp sit
  • The AC and DC ratings of each piece of kit

When you need one

Every G99 application. G98 notifications sometimes need one too, depending on the DNO.

We can create it for you

When you submit an application, you have two options:

  1. Upload your own SLD as a PDF or image.
  2. Ask us to create one. Fill in the equipment details on the form and we'll draft the SLD from them.

Our team then double checks it against the equipment datasheets before submitting.

Common problems

  • SLD doesn't match the inverters listed on the form. Both must be identical.
  • SLD is missing the export CT position.
  • Battery inverter is drawn but not labelled with its AC rating.
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Who signs the Letter of Authority?
Which party needs to sign the LOA, whether the installer can sign it, and how digital signing works.
Why do I need to sign a Letter of Authority?
The LOA is what lets us talk to the DNO on your customer's behalf. Here is what it does and does not authorise.
Still stuck?
Our team can help with your specific application.
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