Thanks, everyone for the great communication. I have spoken to Buffalo and Lincat regarding the same issue and suggested supplying appliances with just the heat flex so the installer can end off into a switched spur or commandos as the plugs seem to melt over time. The 13A fuse surprisingly holds however, the plug is melting and scorching the sockets which are making them brittle.

In regards to moving the sockets to a location away from the heat, I had already relocated them with MK outlets which was difficult due to the limited space in the kitchen with nearby water outlets.

The only option I hadn’t considered was rewiring the appliance as suggested by Broadgage. The last two options I offered the client was what I suggested here, or bring in a new 16mm feed into a DB and then supply what’s needed from there.

I had to replace the fuse holders on the back of the Bain Marie in an Indian restaurant, because they burnt out.

The simple truth is catering equipment has a hard life.

In a situation like this, I always look at what the big boys are doing. Go and look at a McDonalds kitchen, and everything is on Commando sockets, from 16a single phase, up to 63a 3ph. 

I remember when appliances used to say something like 'if the plug isn't suitable for your sockets, replace it and ensure its protected by a 16(15)a fuse 

I would specify RCBOs now, especially with them being metal appliances, in wet places, with concrete floors and most chefs tend to be wet too.

Agreed Johno12345. I have been involved in the hospitality industry most of my working life and anything rated 3Kw or above were connected to Commando sockets on separate radial circuits. If there was a square pin plug on the appliance, it got cut off. 
As an aside, when it came to the robustness of electrical safety in such places, the client had no say. It was my way or no way! 

Annual testing of TED for a showman read for the first show this weekend. 

At the end of last season a plug welded itself into a socket. 

So I told him to take the DB to my usual wholesaler, stand it on the counter and say "We want one of those " so when I came to do the job I would have the right socket. 

So today I started the job and the back plate on the replacement socket was too big,  a quick tour taking in five wholesalers was unsuccessful as they don't stock them, however Toolstation do, still slightly bigger but rearranging the layout sorted that.

Time allocated a couple of hours,  time taken over half a day for a simple job replacing a socket and testing three boards, along with the paperwork. 

I suspect the problem was daisy chained distribution boards with 16 amp leads rather than 32 amp.

I

In the good ones there is a 16A MCB or RCBO per 16A socket when the input is 32A single or 3phase. Thee are some designs that do not do that,  where you can take up to the whole 32A from one 16A skt so long as you do not load the others heavily.

But equally you can get failures for all the normal reasons, corrosion, not fully pushed in, loose wiring in the plug etc all adding an extra half an ohm and resulting in an inability to take the full load.

I do recall adverts for a little wire 'bottle brush' for those sorts of sockets to keep the self heating down,  but I have not seen one in the wild  for years, so  I suspect i is too easy to get  shock off it though.

Mike.

The moral of the story is that when you start getting involved with Ceeform panel fittings and enclosures you soon discover nothing is standard and interchangeable.

So don’t procrastinate and leave repairs until the weekend before the kit is needed, get organised early and you may need to keep some spare fittings in stock yourself.

The incorrect fittings will fit the board that’s lay flat on the floor.

Incidentally, the guy who supplies and runs the generators says if the people in the caravans want them left on overnight there’s going to have to be an additional £100 charge for the diesel this year and don’t lock the generator cabinets, because he does not want them smashed open by people nicking the diesel, as the generators now have white diesel in them and the cost of fuel has gone through the roof, he would rather the diesel was taken without any damage to the machines.