Main fuse protection

[rogerdean]

A cheaper option than have a 3ph supply installed might be installing a load shedding relay that will isolate heavy loads if total gets near 100A.

That's really helpful, thank you! I have set up something like this via my home automation setup - right now if it goes above 22kw then some of the storage heater are turned off. But it's a system that relies on the WiFi behaving so your suggestion is really welcome...

 

[Avo Mk8]

Not to encourage ignoring overload, but the fuse characteristics indicate that a 100A fuse won't blow until sustained current reaches around 130 - 140A. (I guess there's a specific minimum value in the standard, but I don't know what it is!)

 

[rogerdean]

A cheaper option than have a 3ph supply installed might be installing a load shedding relay that will isolate heavy loads if total gets near 100A.

Is there such a thing as a relay controlled by a CT clamp? So a device could be disconnected based on the overall draw? Can't find one but don't know what the right name would be. Thanks again

 

[Mike Johnson]

As DefyG said, it's a load shedding relay, I don't know if they are available in the UK, but in the EU they are available as multiple units that will switch off loads in progression if required to maintain the load below the incoming supply.

 

[nicebutdim]

As DefyG said, it's a load shedding relay, I don't know if they are available in the UK, but in the EU they are available as multiple units that will switch off loads in progression if required to maintain the load below the incoming supply.

Should be Garo units available in the UK. It seems their products have been adopted by quite a few wholesalers since their shower priority board came in for some demand.

 

[rogerdean]

As DefyG said, it's a load shedding relay, I don't know if they are available in the UK, but in the EU they are available as multiple units that will switch off loads in progression if required to maintain the load below the incoming supply.

Thanks Mike, that's what I need. Only things I could find seem just to monitor another single circuit rather than the overall load. A link would be brill if you can... Thanks

 

[rogerdean]

Thanks Mike, that's what I need. Only things I could find seem just to monitor another single circuit rather than the overall load. A link would be brill if you can... Thanks

Thanks for the support folks. Turns out the best way for me is simply to upgrade my EV charger to one that has load management built in, like the Zappi or newer Ohme. Talk about making it complicated for myself eh?

 

[DefyG]

The Schneider A9C15908 is another, not cheap at £500 ish

Available at UK wholesalers (Edmundson & Yesss) but link to;

A9C15908 | Schneider Electric iC60 Series Contactor, 230 V ac Coil, 1-Pole, 90 A, 230 V ac | RS

uk.rs-online.com

 

[Avo Mk8]

Is there such a thing as a relay controlled by a CT clamp? So a device could be disconnected based on the overall draw? Can't find one but don't know what the right name would be. Thanks again

Yes.
Google something like "split core ct current monitoring relay 100A"
This one has the disadvantage you have to feed the tail you're measuring through the hole. You really need a split core version:

https://docs.rs-online.com/5d25/0900766b813e168e.pdf

Came across this, which when set up to the current you want (say 100A) could switch a relay or contactor in part of your installation:

CS-625 AC Current Switch (high output)

Measurement Systems provides CS-625 AC Current Switch (high output) for your business

www.measurementsystems.co.uk

But sounds like you won't need it now