Discuss Contactor wiring, break ring circuit through a stop button in the UK Electrical Forum area at ElectriciansForums.net
Why not use a latch off-key reset stop switch. ?Hi guys , I have to break a ring circuit through a contactor with an emergency stop button .. just want to double check my wiring in the diagram is correct .. haven’t done much of this sort of work so any feedback is appreciated.View attachment 108600
It is a stop button that needs a key to disengage it againWho has decided the Circuit needs an E.M stop and what is the reason for this decision?
Has whoever made the decision thought of the consequences of the EM stop being reset and whatever is plugged in suddenly starting up?
As it would be on 13amp sockets, anything in the future could be plugged in and subject to uncontrolled restart.
Normally anything under Em Stop control would have individual no volt release protection to stop the above happening.
It’s more that when it’s disengaged it turns on again anything plugged in e.g an angle grinder could unexpectedly start up. There is stuff in regs about avoiding rotating machines starting without warning.It is a stop button that needs a key to disengage it again
Hi guys , I have to break a ring circuit through a contactor with an emergency stop button .. just want to double check my wiring in the diagram is correct .. haven’t done much of this sort of work so any feedback is appreciated.View attachment 108600
Why not use a latch off-key reset stop switch. ?
Why ?That would still need a seperate reset control.
If someone is silly enough to leave the key in after going to all the trouble of fitting a key to reset stop.There's a big issue with the key reset type of E-stop in that human nature is to leave the key in it so that you don't loose it. This means the button can't be as easily operated as it should be.
Because, to the best of my knowledge it is one of the minimum requirements for emergency stops of any type, this isngiverned by legislation and not bs7671. I'm far from an expert on the relevant legislation though so yes I may be wrong.Why ?
If someone is silly enough to leave the key in after going to all the trouble of fitting a key to reset stop.
The same could be said for a tripped RCD or MCB do we need a separate reset for them as well ?
I should add, The scenario for this wiring is in a classroom situation , for the instructor to kill the power when leaving the room. There won’t be any power tools used in this scenario so there shouldn’t be any reason for issues with anything starting up when engaging the stop button again .Hi guys , I have to break a ring circuit through a contactor with an emergency stop button .. just want to double check my wiring in the diagram is correct .. haven’t done much of this sort of work so any feedback is appreciated.View attachment 108600
Because, to the best of my knowledge it is one of the minimum requirements for emergency stops of any type, this isngiverned by legislation and not bs7671. I'm far from an expert on the relevant legislation though so yes I may be wrong.
That's only if a fault is still present, it could be that the fault is intermittent, such as a partially cut cable.An MCB or RCD will automatically trip again if the fault still exists, an E-stop will not automatically press itself if reset in error.
If the E-stop fails to latch in the off position for any reason then having it electrically latched and requiring a second deliberate action to reset it will prevent a dangerous situation.
So it’s not an emergency stop?I should add, The scenario for this wiring is in a classroom situation , for the instructor to kill the power when leaving the room. There won’t be any power tools used in this scenario so there shouldn’t be any reason for issues with anything starting up when engaging the stop button again .
Having said this , will the wiring be ok ?
The wiring is fine.I should add, The scenario for this wiring is in a classroom situation , for the instructor to kill the power when leaving the room. There won’t be any power tools used in this scenario so there shouldn’t be any reason for issues with anything starting up when engaging the stop button again .
Having said this , will the wiring be ok ?
We don't know what the instructor is trained in, he may be only good at sticking soles on shoes.The instructor will be the “trained” individual and will know that all machines are off or unplugged before turning on the circuit.
They have asked for the stop button that needs key to renegageSo it’s not an emergency stop?
Just an isolator?
Simple on/off switch to control the contactor would be fine.
The instructor will be the “trained” individual and will know that all machines are off or unplugged before turning on the circuit.
The contactor would be a N/O with a N/C stop switch.They have asked for the stop button that needs key to renegage
I should add, The scenario for this wiring is in a classroom situation , for the instructor to kill the power when leaving the room. There won’t be any power tools used in this scenario so there shouldn’t be any reason for issues with anything starting up when engaging the stop button again .
Having said this , will the wiring be ok ?
Reply to Contactor wiring, break ring circuit through a stop button in the UK Electrical Forum area at ElectriciansForums.net
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