Yes, you can get gennies with 16A 240v output. Some offer 13a and 16a.
It's an expensive option, mate. You would need at least a 4.5 kva or larger, and if you are near dwellings it would need to be the silent type. I would expect it to cost around £150 a week for hire, probably more. You'd need to get all your welding jobs set up at once, then just hire it for a holiday (!) week to get it all done before it went back. It has been done before, though, so it could be an option. You have to have good security for the genny; pikeys love gennies!
You won't need to fit a new fuse into the existing box. You can run a 16-20A cable from the output of the 30A fuse through the grommet directly above, along the wall to a wall-mounted small 4-way consumer unit box. This box would have an isolation switch, like your fuse box. This would be your dedicated welding supply. The box would contain a 16A mcb, and preferably a rcd, although this isn't essential, but safer.
From your cu box a 16A preferably armoured cable would run to a 16A wall socket. You would plug your welder into this socket. In the event of any problems on the welding side, the 16A cutouts in the cu box would operate, tripping out and protecting your original fuse box.
All the above could be done without altering your present council fuse box in any way, apart from a new output cable from the 30A fuse. If you moved away, all could be removed easily and taken with you.
Any competent electrician who didn't talk too much could do the job in an hour, including testing. About £30 - £40 around here. The bits would cost rather more than this, but an obliging electrician might be able to get these at wholesale price for you.
The council cant stop you having the work done. They can make you ask first & they can insist that it is done properly by an approved contractor. Do you think that no council tenants any where ever do improvements to council owned property?
Looking at it closer it seems that the 30 amp fuse supplies the sockets on a spur. You could convert that to a ring & fit the fused outlet for the 16amp plug on to that ring.
(I think please ask a spark first)
Or do the lights need to be on separate fuses? Put them on one & then buy a new fuse of a higher rating to make the new supply for the 16 amp sockets.
I think any thing you do do would need to be done by a sparky any way. So get their advice.
just take a 2.5mm flat twin and earth cable out of the 30 amp fuse down through a double pole 25 amp or a 60 amp rcd with a 30miliamp trip into the 16amp socket . then down rate the fuse from 30 amp to 16 amp as it shouldnt be a 30 amp feeding 2.5mm radial cable that is allready there
typical councill job no earth ring on the incomer armoured . the fuse shouldnt be rated at more than 20 amp on 2.5mm cable . if it had been wired in 4.0mm cable to sockets a 30 amp would be ok
Wonder how old is the wiring? It must split at the junction above the box. Certainly agree a 20A fuse would be safer on 2.5 mm, but that old 2.5 mm cable on a 13A circuit was rated up to 24A when new, and was supposed to carry 30A well long enough to blow a 30A wire fuse without serious problems. But it does deteriorate with age and use.
So if there are two separate circuits either would carry enough current to burn a 30A fuse long before the cable got to overheating and burning out. At least that was the thinking at the time, which is probably why they've stuck a 30A fuse in there. Modern 2.5 mm is still rated up to 24A continuous, I think, but may have more safe leeway. Certainly 4 mm is a much safer alternative, with less volt drop, too.
With a separate new cu to isolate the old fuse box there shouldn't be a problem, even if the 30A runs two old 13A circuits as well. It is highly unlikely there will ever be a drain of anywhere near 30A on the old fuse.
Each old 13A single socket in each garage will have a plug 13A fused at max.
Weldinator is unlikely to be running a 3-bar electric fire or anything else juicy in his while he's using his welder from the new 16A circuit, so his draw is only going to be around 12-14 Amps max, and most of the time a lot less. If the guy with the other garage gets into heavy welding from his 13A socket at the same time (highly unlikely!), or starts up a huge compressor, he will blow his own plug fuse at 13A - 15A.
If there are any fluctuations on the circuits the rcd will trip out anyway, so it might be a good idea to get a consumer unit with one on board. Or you can get a 16A wall socket with an rcd installed.
If you mean the cost of the rcd with 16A wall socket, this is generally the most expensive item, for new about £100 from RS down to around £70 from some suppliers. Cheapest secondhand from a site electrician, around £30 - £50.
Sometimes they appear on ebay for less. From caravan equipment sellers you can get the in-line trailing sort, where you plug one end into the 16A socket, the rcd sits in the middle, and the other end has a socket for you to plug your welder cable into. These are cheaper new, around £30 - £40 if you can find one.
Before buying take advice from the electrician about which sort would best suit your intended use, but be aware of prices so you don't get ripped off.
As many electricians work on sites they build up a little store of surplus items, and can often be cheaper than hunting down all the bits by yourself.
try www.tlc-direct.co.uk I got a 6 way CU for £15 and rcd for £12.50. mcb fuses £1.99 for type B or £3.80ish for a 40A type C, I was advised a type C was better for a welder. all that gear was contactum make. 10mm tails for the consumer unit are around £1 per meter. 2.5mm grey 2 core plus earth was under £2 a meter and 6mm two core and earth was £2.60ish per meter.
the blue wall socket was about £11 and the plug was about £9.50 the arctic blue cable is about £1.30. these prices are plus vat.
tlc direct do have quite a few stores to collect or mail order, you can place your order online to collect and pay instore, saves waiting for them to pick the order for you... i found them really helpful.
hth