You appear to be missing a square Tufnol rod with the blades that engage in the slots on the ceramic connection block and the mechanical parts that engage with the door switch handle. They were not my favourite isolator as the mechanical parts were not difficult to damage if the door was not properly closed. Personally I would not use it and buy a more modern unit. The neutral was not usually switched and if required a neutral block was fitted, I don’t think it was optional so it also appears to be missing.

Mike

Edited By Mike Poole on 07/11/2022 19:56:47

Edited By Mike Poole on 07/11/2022 19:59:48

If you are the owner of an industrial unit and you need it wiring up, you would install five pin sockets, complete with neutral. That way, you can plug any machine into them. If you install both four and five pin sockets, you guarantee that you will park a machine that needs all five pins next to a socket that has only four.

If you bring a machine into a workshop that is only equipped with five pin sockets, you would put a five pin plug on the machine whether it needed it or not as that will be the only way to make it run.

As said by others that type of switch does have a tendency to malfunction, but if you have overcome this with years of use carry on.

The isolator wouldn't be installed now in an industrial situation as there is no provision to Lock Off for machine maintenance.

A new enclosed 16A TP IP65 rotary isolator costs around £15 so perhaps replacing would be good advice.

Emgee

His current arrangement is one that was not part of the manufacturer-provided system. He says the isolator box 'had been totally bypassed' so he is seeking to revert it to the factory-spec.

While what you say is true, it does contain two assumptions that are necessary to make it function.

First, that the switch-socket is easily accessible when you want to isolate the machine – i.e. you do not have to move a tool cart or climb up on top of the machine to access it. A switched isolator located on the machine itself, within arm's length of the place you stand when operating it is more likely to be used.

Second, three phase switched isolators are expensive and will duplicate the function of the one he already has. One of these correctly wired up is all that is needed screwed to the wall:

https://www.screwfix.com/p/abb-16a-3p-e-surface-socket-415v/5699f

A prudent person wanting to work on the machine would first isolate it at the box he shows and then physically unplug it from the socket.

Hi, note to OP , it is most important to make sure that behind the porcelain block with the terminals and contacts there should be a yellow/brown insulation card, this must not be ommited on reassembly as I have personal experience of flashover occuring if it is missing!!

Phil

Normal manufacturer installed isolation switches relate to factory conditions and are usually intended to simply lock out a machine to prevent use pending repair, servicing or other operations. Commonly they are somewhat out of the way being low down on the side or even rear of the machine. Its not generally considered necessary to be especially easy to see if the machine is turned on or off. In most places a damn great "Don't Use" label gets plonked on top when its turned off.

Risks in the home shop are a bit different. In my view the primary "Ooops, shouldn't have done that!" to avoid when it comes to power is inadvertently starting a machine because you'd forgotten it still had power to it.

I like these Lewden ISO series lever type isolators feeding a 5 pin round plug and socket for my 3 phase machine supply.

The isolators are screwed to the wall close to chin / eye level so a quick sweep of the eye when coming in or moving around the workshop makes it clear if a machine has power or not. Even from a significant distance. Like all proper isolators there are holes for a lock off padlock. If its just me pulling the plug is fine but if I have a guest worker something a little more positive is desirable.

I loathe the round operator isolators because you cannot clearly see if they are on or off from a distance.

Objectively the Lewdens are a bit on the plasticy side but they work well enough with a satisfying clunk when operated and the terminal blocks have plenty of wire room. The front screws are prone to shear if you get heavy handed with a screwdriver tho'. Cost is around £25 I think.

Clive

Edited By Clive Foster on 08/11/2022 15:50:44