Below is a step by step guide to working through the processes.
Step 1. Obtain the formal application document. Your local DNO may have their own preferred document, so you should contact them and ask for it.
If you know who your DNO is, their contact details can be found here:-
If you don’t know who they are, a post code search can be carried out here:-
Step 2. Complete the form. You will need to know whether you intend to export electricity onto the grid (for the purposes of getting paid for it), or whether you intend to just use the power within your own building or facility. You will also need to know information about your maximum site demand and other technical information such as the fault current rating for the proposed generator.
Step 3. Submit the form, and pay the fee. Most DNO’s will charge to process the application and / or to carry out the network survey.
Step 4. Liaise with the DNO during their investigative phase. They will carry out a survey to confirm that their local network can accept your proposed generator connection. There is usually extended communication back and forth during this process.
Step 5. Agree the outcome. Normally approval will be granted and sent to the applicant. In some cases the DNO may require changes to the connection method, or upgrades to the local grid. These would need to be paid for by the applicant if required.
Warning: The above DNO can take up to a maximum of 65 working days to process your application, so start in good time.
Obtain and install the necessary G59 Protective Relay, breakers, and any other equipment associated with power exporting if required etc. These are usually supplied by shentongroup as part of a bespoke Site Interface Panel, but can also be built in to your mains electrical intake if required. This can also be built into the CHP or generator switchboard if approved by the DNO.
Testing & Certification Process
Before the generator can be used, the G59 protective device must pass a series of functional and safety tests. These need to be carried out by a trained engineer, using a suite of calibrated test equipment. The test engineer and his equipment are normally provided by shentongroup. The test usually has to be witnessed by a representative from the DNO. There is usually a charge for this, although their fees may be wrapped up in the application fee or network survey fee.
Unless you are very familiar with the processes outlined above, going from the initial G59 application through to achieving final sign-off can be a daunting and time consuming task. Use the following to ensure that you’ve thought of anything that may not have been considered or that could slow the application process.
How do you locate the relevant DNO?
Can you project manage the process, complete the application forms, submit them to the DNO, then liaise with them throughout the process, including chasing them up to keep the application running on time? How will you deal with any technical queries they raise?
An additional fee may be charged by the DNO for the network survey, have you budgeted for this?
As a result of the network survey, the DNO may require network changes or upgrades as a prerequisite for granting approval. Have you allowed for this in your timescales?
It is standard practice for a ‘Site Interface Panel’ to provide the actual G59 devices, breakers, and any other equipment associated with running in parallel to the grid. It is common for the equipment to be in a separate electrical enclosure, but it can also be incorporated into the generator panel sometimes. Likewise, it can also be built into the CHP or generator switchboard if approved by the DNO. The requirements of this area are specific to each individual installation, and usually require liaison with the electrical contractor on the project.
G59 Accreditation Test
For the G59 safety and functionality testing you must provide a trained engineer, with a suite of calibrated test equipment. A CHP or generator engineer from the manufacturer will also need to be in attendance. An engineer from the local DNO will generally be present to witness the test, and as previously mentioned, there is generally a cost levied by them for their attendance.
Read this post to find out more about what is G59 or contact our Technical team on +44 (0) 844 888 444 5 who can deal with your requirement.