That head is going to contain a BS 1361 fuse rating unknown. It is on a loop supply so not likely to be a 100A.
You cannot have a vehicle charging point on a loop supply so if this is being considered contact the DSO (AKA DNO).
BS 951 clamps were fitted to PILC lead sheaths by the million up until about 2005.Nowdays they are replaced with a Hepworth constant pressure spring fitted over a braid having cleaned up the lead with a bit of wire wool and then all taped over with self amalgamating tape. No more sweating a conductor on to the lead as that is indoor hot works which presses all the H&S alert buttons.
Don't try and tighten the 951 yourself as you could crush the lead and short the conductors together through the paper insulation unless you are wearing your brown trousers and full face protection.
Thanks everyone for your posts so could be a 1361 or a88 fuse So I’m putting in a new cu but just wanted to know what fuse it is for the paperwork and yep I know the grey box is an isolator
BS88 -3 has replaced BS1361, but the physical fuses sizes have not changed, just the details of the writing stamped on them, so it may say either depending when it was last blown and replaced.
Unless you have a very high PSSC (like >30kA then there is no change in conclusion)
Code? is that something that should concern the DNO? The service looks perfectly ok, as the "tester" comments, a low impedance. Although obscured, the method of bonding the two lead sheaths together is likely to be as was done in those days, a 7.029 plumbed between the cables, and "improved" with a 951.
Have I missed anything? Oh yes, the ISCO cut-out, the fusing as far as the curious are concerned, N/V, (not verified) Out of scope of the BS7671.
Thanks everyone for your posts so could be a 1361 or a88 fuse So I’m putting in a new cu but just wanted to know what fuse it is for the paperwork and yep I know the grey box is an isolator
You want to know because?
The suppliers fuse may be overloaded?
The tails may be overloaded?
Zs is too high to blow the fuse?
The main switch in the CU may be overloaded?
The RCDs in the consumer unit may be overloaded?
Just to fill a box on the certificate?
Have I missed anything?
If none of the above is a potential issue can’t you just go with N/V in the box?
I guess the main issue is verifying that the fuse is <=100A. Without knowing that the cutout is of a type which only accommodates <=100A fuses, you're into speculation territory - which has implications for things like the max rating of CUs and their isolator switches and SPDs etc.
Would it be too difficult for the DNOs to attach a sticky label to the service head when they install a fuse?
I suspect that even a 63 A fuse is sufficient for most people most of the time, but demand in certain households may be well above what existed originally. Even in the 1980s we were happy with only one bathroom and if there was an electric shower, it was probably only 3 kW. The only EVs in those days were milk floats.
Would it be too difficult for the DNOs to attach a sticky label to the service head when they install a fuse?
I suspect that even a 63 A fuse is sufficient for most people most of the time, but demand in certain households may be well above what existed originally. Even in the 1980s we were happy with only one bathroom and if there was an electric shower, it was probably only 3 kW. The only EVs in those days were milk floats.
I've got an 8.5kW shower on a 60A supply. Nothing has gone wrong yet.
I'm not sure what will happen when I buy an EV one day. I don't see why I can't get a 16A 3.6kW one, rather than teh usual 32A 7.2kW.
For assessing if the installed newly installed consumer unit is okay I would assume it’s got a 100 amp fuse.
For assessing if an EV charger or a similar big load can be connected I would assume it’s a 60 amp fuse.
As JP said it isn’t suitable for connecting an EV charger to and I would not recommend a shower larger than 8.5 kW.
The only way to find out for certain is to ask the DNO and they will probably need to come and open the box. That’s a lot of hassle for them just for you to fill an entry on a certificate, if you assess it’s okay with either a 60, 80 or 100 amp fuse just write N/V in the box and crack on with the next job.
