Understanding requirements to connect an electricity generating system to the grid

May 27th, 2010 by Gavin Lanoe

The only really easy way to generate and use your own power is to connect your micro generation system to the wiring in your house. This requires you to have a device called a ‘grid tied inverter’ this raises the power generated by your panels to the voltage used by your house.

I’ll go into the specifics of grid tie inverters in another article but for the time being the only thing to know if you need to involve your local electricity provider in the connection of such a device.

Guernsey Electricity requires the completion of two forms before beginning the installation process.  One form is for the “Application for a new supply, additional load and/ or alterations to Electricity supply.”

With this form you tell Guernsey Electricity Ltd. how many sockets and lights you have.  You have to include the power requirements of any heavy load devices such as an electric shower, a cooker and a wall mounted or immersion heater.

The second form gives the power provider information on how much power you could potentially generate.  This form is for massive private electricity producers.  An applicant will need to fill-in basic information.  Most of the values can be found in the manual for the inverter that you purchase.

Seek advice from an electrician or from Guernsey Electricity Ltd. on anything you don’t know. If you fill-in the forms incorrectly Guernsey Electricity Ltd. may not let you attempt the installation.

I’ve had a good technical discussion with Guernsey Electricity Ltd.  They have confirmed that they will install two additional electricity meters into the system.

• One meter goes between the inverter and the home fuse board. This meter tells you how much power your system has generated in total.

• The second Meter goes in parallel to the main house meter. This meter tells you how much you have sold to the electricity grid.

Guernsey Electricity Ltd. currently pays £0.063 for every unit (kW.h) sold back to the grid. Whilst this isn’t as attractive as that paid in the UK it is an effective way to obtain credit for units used overnight.

I now need to have a discussion with them on the positioning of the connections to the fuse box and a Maintenance Isolator.

I also need to find out what the purpose of the Maintenance Isolator is. Is it for the Power Provider to be able to cut the system out if they are doing maintenance on the power cables?

The end of this section basically is to talk to your provider as to what they require. If you start the conversation knowing the lingo then you will probably get a better response.  For help enlist the services of a qualified electrician.

This article is available also on my website.


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