Start stop switch

[netblindpaul]

agree with that. there's no problem with fitting extra stops as a matter of safety and easy reach, but there should never be any means of starting machinery remotely as that would be a major safety issue.

telectrix,
There are problems with adding more stops as you can fall foul off HSE guidance for compliance with PUWER98 depending on the original system.
In which case IF there is an electrical issue on the system, even though you have improved one aspect of safety you can reduce another and move the employer into a non compliance situation, and then get yourself into trouble for incompetent design not in accordance with statute law, ACoP's, CoP's & industry guidance.
Remember the LVD & the MD.

 

[telectrix]

agreed. i was thinking more on the lines of fitting e stop/s where they would be sited in the best interests of safety.

 

[Silly Sausage]

Paul

Out of interest, could you elaborate on the problems with having multiple stops.
I used to work on Chemical plants etc, (instrument work so no electrical stuff), so I always thought you could have as many STOP buttons as you liked. Invariably a local one and very often there were remote ones as well, seems to be a very sensible way of doing things.

 

[netblindpaul]

You can have as many as you like Archy, in fact the more the merrier.
However, if the control system is not in compliance with BS EN 60204-1 then you have issues.
I used to be acceptable to run 2 phases through a metal emergency stop button.
Thus when operated you had what is now a 400V a.c. potential across the button.
I very much doubt that you would ever come across this in a Petro/Chem environment.

 

[Silly Sausage]

You can have as many as you like Archy, in fact the more the merrier.
However, if the control system is not in compliance with BS EN 60204-1 then you have issues.
I used to be acceptable to run 2 phases through a metal emergency stop button.
Thus when operated you had what is now a 400V a.c. potential across the button.
I very much doubt that you would ever come across this in a Petro/Chem environment.

Mmmmm, I suspect I'm getting well out my depth here, but what the hell...

I almost had a whinge about BS ENs the other day but I deleted it, most people have no access/can't afford to buy them, I'll leave that one there.

In this case, the way I read it as...this is a 3 phase motor driven system, surely it can't take much thought, of which I'm not particularly capable of at the moment, to have any stop switches on anymore than 230v?

 

[netblindpaul]

Thing is you are not allowed to run control across 1ph & N either.

 

[spark 68]

Thing is you are not allowed to run control across 1ph & N either

Would you mind elaborating a bit further please Paul, as this is intersting stuff

 

[Silly Sausage]

Would you mind elaborating a bit further please Paul, as this is intersting stuff

If I can find them I'll dig out some of my old (2000) loop etc drawings and scan them if you want.

I seem to remember the interlock jobbies needed a bit of thinking about.
We only got -------eds once for missing something.

 

[spark 68]

If I can find them I'll dig out some of my old (2000) loop etc drawings and scan them if you want.

Please if you don't mind, I did some control and interlock wiring (with drawings), and Iam sure on that occasion it was all 24 Volt stuff, and mechanical interlocks (both cable and castell keys), I do have a BS document somewhere about E-stop circuits.
Thanks

 

[Silly Sausage]

Would you mind elaborating a bit further please Paul, as this is intersting stuff

It is.

If I had my time again I'd have left school and got in with an Instrument company/job.
Could have travelled the world by now, free and single, earned a wedge of of cash....

The past has gone, look forward to the future

 

[Silly Sausage]

Please if you don't mind, I did some control and interlock wiring (with drawings), and Iam sure on that occasion it was all 24 Volt stuff, and mechanical interlocks (both cable and castell keys), I do have a BS document somewhere about E-stop circuits.
Thanks

You might have to hassle me by email but if you want anything I'll see if I can find it.

 

[platty1005]

Hi dacosta this sounds like a 3 phase isolator feeding a 3 phase DOL direct on line motor starter with the stop start buttons on the front. The control circuit inside is probably 400V with NO overcurrent protection as the wiring is all inside the starter. Therefore it is not really safe to try and wire additional stop start buttons. If the (buttons) starter is in the wrong place it may be better to move the starter than try to wire extra stop start buttons.

 

[Knobhead]

We seem to be heading off at a tangent as usual. There is no mention from the OP of the control voltage!

 

[Kamikaze]

And I think he was more interested in starting the motor rather than stopping it. :smile5:

 

[netblindpaul]

We seem to be heading off at a tangent as usual. There is no mention from the OP of the control voltage!

Thing is Tony under current statute law machine modifications should be done to BS EN 60201-1, if the control system does not comply with this which is doubtful if it is an old machine, then, the control voltage is relevant to whether it is feasible to add additional control devices without the end user falling foul or PUWER98 legislation.
Additionally, would it really be a good idea to run unfused 400V control wires along a conveyor, now even if this was a CE marked machine if it is classed as a simple machine then unfused 400V control is acceptable under 60204-1.
If you add more control devices then it is no longer a simple machine etc.