What is G59 and How Does it Relate to my Generator and Combined Heat and Power Supplies?

It’s a regulation that’s in place to ensure the safe connection of generator devices that run in parallel with mains electricity on the national grid and it covers an array of standby generators and combined heat and power systems.

G59 was initiated following Ofgem rules and is administered as the Energy Networks Association Engineering recommendation G59/3-1 “Recommendations for the connection of generating plant to the Distribution System of Licensed Distribution Operators – Amendment 1”. So in simpler terms, G59 regulates the connection of all combined heat and power units and generators used for peak-lopping, or grid parralel use greater than 16a per phase. Anything lower than this, G83/1-1 applies.

The legislation ensures that no generators can be connected to the national grid without the knowledge and permission of the local electricity authority, with the purpose of preventing the embedded generator from sending electricity onto the National Grid in a dangerous manner.

shentongroup provides a specialist G59 relay protective device that automatically disconnects the embedded generator from the mains in certain situations. It monitors the stability of mains electricity and is programmed to certain parameters dictated by the District Network Authority which typically include; voltage, frequency, ROCOF (rate of change of frequency) and phase angle. Should any of these parameters go outside of programmed limits, the relay triggers a protective device to break the circuit, instantly and safely disconnecting the generator from the National Grid.

We’ve a more detailed guide to G59 Embedded Generator (CHP) Applications here. that can be downloaded here, but to learn more about G59 regulations, shentongroup staff are highly trained to address your questions on connecting your uninterruptible power solutions to the national grid. To speak to a member of our team, get in touch now!