Bs En60309/ Commando 5 Pin Socket Without A Neutral

[toolsparky]

Hi. Do the regs state that only a 4 Pin socket outlet, should be used with 3 phase and earth cable and never a 5 pin??

Today a contractor turned up at our engineering factory with a Space age £80,000  German Laser welding machine to do some specialised on site welding. He plugged his 16 amp 5 pin socket into our wall socket, tried to operate his machine and it Juddered like mad and blew an internal 6 amp MCB!

 I was asked to check out the supply to the socket and found there is no Neutral wire to the Neutral pin. I then found an alternative socket that has 3 phase, neutral and earth supply, but as soon as the machine was connected to this supply (even though the welders isolator was turned off), the 6 amp Internal MCB would blow again.

 In the past the socket has just been used for a  Balanced Neutral Motorised polishing machine, but I guess this Welder, having electronics galore and 230v internal circuits may have been damaged in some way, by the lack of neutral. What implications does the lack of a Neutral have for a machine of this type?

 The socket was fitted several years ago by one company and there have been 2 PIR's since from different electrical companies that have not flagged up a problem with this socket or the fact that maybe it should have been 4 pin rather than 5.

Obviously the contractor with the welder isnt happy that he has potentially very expensive repairs to face and is trying to blame the company I work for, even though we did our bit with regards to regular PIR's.

 You would think that a sophisticated machine like that would have some kind of protective circuitry in case of a floating Neutral. Also it was strange that it tripped the internal MCB even though the Machines isolator was off!

Any comments or advice greatly appreciated

 

[steptoe]

yes

what would you think would happen if someone plugged something in that needed a neutral?

this guy has just had 400v put across potentially 230v terminals in his welder,

deffo the companies fault.

you pay the welder guy, then you get your money of the PIR company, depending on the limitations though,

 

[Steve3948]

German machine, colours in his plug should be checked.

I assume he's used it in a UK socket before ?

Sounds like one or the other is connected to incorrect terminals.

 

[Andy™]

5 pin socket must be wired with a neutral. if there is no neutral then it should be 4 pin. and whoever done your PIR's is incompetent

so it looks like you need to pay for his machine to be fixed, or maybe claim from the spark who missed it on the EICR

 

[Steve3948]

Extract post form a Mig-Welding forum,

We have literally hundreds of pieces of 3-phase equipment and leads. I've never used anything that utilised the pilot pin and none of our leads use it. We don't use neutral either though we do use the 5-pin plugs because it's by far the most common outlet to be found.

Sounds like welders know better then  :red card  

 

[steptoe]

Yer, you can plug something NOT requiring a neutral into a 5pin plug even if there is a neutral there, but you can't run something requiring a neutral off a supply without a neutral.

 

[Andy™]

Extract post form a Mig-Welding forum,

We have literally hundreds of pieces of 3-phase equipment and leads. I've never used anything that utilised the pilot pin and none of our leads use it. We don't use neutral either though we do use the 5-pin plugs because it's by far the most common outlet to be found.

Sounds like welders know better then  :red card  

the 'welders' in your quote have done nothing wrong

fact is, many places have 5 pin installed regardless of it needing a neutral or not. if it doesnt, then dont connect a neutral in the plug. but at least the neutral is there for something that does. you can easily go 5 pin to 4 pin, but not 4 pin to 5

all my TP sockets are 5 pin. all the extensions are 5 pin. but my TP welder doesnt need neutral, so the flex is just 4 core. which is how many fabrication shops etc are

 

[OnOff]

German machine, colours in his plug should be checked.

I assume he's used it in a UK socket before ?

Sounds like one or the other is connected to incorrect terminals.

Two blacks, a brown, a blue and cpc I bet, often a blue /black mix up

 

[ProDave]

A decent phase sequence / over volt relay in the control panel would stop the machine turning on so it can't self destruct. :innocent

 

[apprentice87]

Sounds like the welder was knackered anyway. How can it still trip internal MCB's when its isolator is turned off??? wiring in welder plug wrong i reckon.....

john...