dombanks Posted September 18, 2018 Share Posted September 18, 2018 How do you know if you need to upgrade the main fuse from your house from 60A Seems like the company that does it is UK power networks and can cost from 0-1100 quid Quote Link to comment Share on other sites More sharing options...
Rory's Dad Posted September 18, 2018 Share Posted September 18, 2018 Does your 60A one go bang every so often? Quote Link to comment Share on other sites More sharing options...
dombanks Posted September 18, 2018 Author Share Posted September 18, 2018 No so I'm not even sure it needs it but the wiring is ancient... 4 fuse box: 1 socket ring, 1 light, 1 cooker.. A random spare... no rcd A separate rcd unit for the shower... Which trips when her indoors uses the shower without exception total dogs dinner. I was reading about getting the CU upgraded to a new one and it seemed to crop up a few times. We are just trying to prioritise the expensive jobs Quote Link to comment Share on other sites More sharing options...
Kit Car Electronics Posted September 18, 2018 Share Posted September 18, 2018 I'd prioritise a new RCD consumer unit, earth bonding and checking the shower wiring above everything else, personally. 60A is plenty enough to kill or start a fire... 1 1 Quote Link to comment Share on other sites More sharing options...
Kevin Pullen Posted September 19, 2018 Share Posted September 19, 2018 If your 60A fuse is going pop on that CU it needs replacing as Mike has said with a new CU with RCD but chances are you may need some wiring done altered Quote Link to comment Share on other sites More sharing options...
corsechris Posted September 19, 2018 Share Posted September 19, 2018 The rating of the incoming fuse is about the capacity of the supply, not your own consumer kit, so that probably explains the variable costs. Nowt if the supply is up to providing 100A, up to £1100 if they need to run a bigger feeder (assuming its even feasible). Certainly, updating your own side of things with a re-wire sounds wise though..... FWIW, we have an 80A fuse on the incomer and not had an issue. Peak demand I've seen from time to time has been around 9kW (40A), so well within the 80A we have and also the 60A you have. If you had a 7kW EV charger (32A) and had the oven, microwave, kettle, MIG welder, vacuum and 60" plasma telly on all at once, you might push your luck When we moved in here we had an old CU with 6 circuits I think it was. House had been rewired at some point in the not too distant past but the CU had been left. Our supply is overhead (TT) so came in through a big RCD anyway. Now have a new split-load CU with 2 RCDs and many more circuits, mostly just for convenience. 1 Quote Link to comment Share on other sites More sharing options...
Kevin Wood Posted September 19, 2018 Share Posted September 19, 2018 Yep, as said, the fuse rating might well be down to the local supply cable and the diversity that was applied to the whole system when it was installed. Unless you're blowing it regularly, there's no need to worry. If you only have 4 circuits in your system it's unlikely you'll get anywhere near it. You do need to get the shower looked at, however. If it's taking out the RCD it has a fault somewhere. Quote Link to comment Share on other sites More sharing options...
dombanks Posted September 20, 2018 Author Share Posted September 20, 2018 How do you figure out diversity? Being the physicist I am it sounds a bit like maths lol. I get that a cooker is an obvious one as in reality you are unlikely to use it all at full power all the time but what About other stuff i suppose it's why you can have technically mtechnically more A of stuff that your fuse is. The house fuse hasn't blown at all but while I had an electrician in I wanted to be a bit future proof. Annoyingly the supplier just upgraded the meter so had it out but wasn't allowed to change it!! The CU is pretty much the top of the list anyway. I can't power the garage without a change, and we are thinking of an extension/new kitchen with an induction hob (if that makes any difference) so I guess I'll need more space Cheers all Quote Link to comment Share on other sites More sharing options...
Kevin Wood Posted September 20, 2018 Share Posted September 20, 2018 In the same way that a cooker's fuse rating is based on a diversity calculation - i.e. on an assumption that it's unlikely that all elements will ever be turned on at exactly the same time, this is also the basis on which the local supply will be designed. How this works out depends if the houses were originally built with gas, electric or oil heating and other factors, but often the supply is designed on the assumption of only 1 - 2 kW of load for each property. Average that over the few hundred houses that will be fed (in an estate scenario at any rate) from a given substation and that will be how they size the transformer. The transformer will probably get overloaded for short periods of time, e.g during TV commercial breaks when everyone boils their kettle, but they have huge thermal inertia, so are designed to cope with this. The fuse rating given to each property also drops out of this calculation, and also whether they could upgrade it without a major headache. It will be interesting to see how things develop if electric cars take off extensively, and houses start getting charging points that draw heavy currents for hours on end. It's probably well worth upgrading the CU given your plans. Modern breakers (I'm guessing yours might even be wire or cartridge fuses?) are much quicker acting in the event of a fault and RCD protection is the norm these days, which significantly reduces the risk of a fatal shock. I still think you'll be fine on a 60A main fuse, though. 1 Quote Link to comment Share on other sites More sharing options...
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