Electric boilers and DNO notification

[sbwattam]

My company has recently done some air source heatpumps which require DNO notification and EV chargers which also require DNO notification. On an EICR today came across a 14.4kW electric boiler on a 60A supply (installed last year by others). Apart from the obvious issues I looked into whether these should also be notified to DNO but everything I find seems to suggest electric boilers do not need to be notified, even though they can be 2x load of EV point!
Does anyone know if this is correct?

 

[mainline]

My company has recently done some air source heatpumps which require DNO notification and EV chargers which also require DNO notification. On an EICR today came across a 14.4kW electric boiler on a 60A supply (installed last year by others). Apart from the obvious issues I looked into whether these should also be notified to DNO but everything I find seems to suggest electric boilers do not need to be notified, even though they can be 2x load of EV point!
Does anyone know if this is correct?

Basically no they don't but :You must notify your local DNO if you make any significant change to your connection, such as installing one of the following energy devices:

• solar photovoltaic (PV)
• heat pump
• electric vehicle (EV) charge point
• battery storage

https://www.energynetworks.org/industry-hub/resource-library/low-carbon-technologies-combined-installation-process-flow-chart.pdf

 

[sbwattam]

I was aware of those, even gov.uk website specifies those. I know what your suggesting is that it is a significant alteration but the DNO form has no section for anything other than PV, EV, Heat pump or batt. storage. It seems strange electric boilers are not listed given their potential current draw and extended periods of use.

 

[mainline]

I was aware of those, even gov.uk website specifies those. I know what your suggesting is that it is a significant alteration but the DNO form has no section for anything other than PV, EV, Heat pump or batt. storage. It seems strange electric boilers are not listed given their potential current draw and extended periods of use.

It's left to the electrician to decide, after all he's the one responsible for the design and installation and i suppose upto him whether to phone the dno and for them to say no

 

[Other_Tucker]

Do you mean a incoming 60A supply or a 60A circuit to the boiler? I've seen a 50A distribution circuit and a 40A shower, 32A Hob, 32A Cooker and 4x32A sockets ++ etc on a 60A head

ASHP's are basically a pump and a fan, they aren't large equipment, and if your PV is less than 16a per phase the DNO just needs a form filled within 28 days

 

[sbwattam]

Do you mean a incoming 60A supply or a 60A circuit to the boiler? I've seen a 50A distribution circuit and a 40A shower, 32A Hob, 32A Cooker and 4x32A sockets ++ etc on a 60A head

ASHP's are basically a pump and a fan, they aren't large equipment, and if your PV is less than 16a per phase the DNO just needs a form filled within 28 days

The cutout is 60A, boiler rated at 14.4kW which is 62.6A but supply circuit is 40A MCB. I don't know if there is some way to limit max output on the boiler in the settings as 40A MCB seems to be holding. We didn't install so no idea how it's been set up. But there is also induction hob and oven in there as well.
Maybe the service fuse has been replaced with a section of galv conduit!

 

[Other_Tucker]

The cutout is 60A, boiler rated at 14.4kW which is 62.6A but supply circuit is 40A MCB. I don't know if there is some way to limit max output on the boiler in the settings as 40A MCB seems to be holding. We didn't install so no idea how it's been set up. But there is also induction hob and oven in there as well.
Maybe the service fuse has been replaced with a section of galv conduit!

If you look back at the time current graphs for a type B 40A MCB, the trip time at 62.6A is apparently a long shower or the time taken to boil a hot water tank.

 

[freddo]

I don't know if there is some way to limit max output on the boiler in the settings

A lot of electric boilers have multiple elements, it's usually just a matter of unplugging one of them. Most ramp up by switching the elements on in sequence depending on the demand required, unplug the last stage. The last 2 I wired all had the 6th stage disconnected at the factory, the element and live wiring was there, just not connected to meet the rating plate of that model.

 

[sbwattam]

A lot of electric boilers have multiple elements, it's usually just a matter of unplugging one of them. Most ramp up by switching the elements on in sequence depending on the demand required, unplug the last stage. The last 2 I wired all had the 6th stage disconnected at the factory, the element and live wiring was there, just not connected to meet the rating plate of that model.

Thanks. I suspected that might be the case, was aware a 40A MCB would take an overload of full 14kW load for a few minutes or so, but apparently its been fine, MCB isolated circuit ok so no welded contacts. We were there to do EICR so not going to start stripping down electric boiler to satisfy our curiosity!