Does a 20amp emergency stop button exist?

[mainline]

As opposed to arguing the right and wrongs, what is your background.

I worked in electronics and programming for over 40 yrs before semi retirement and now work to suit mostly repairing various radio test equipment from all over the world, for 3 days a week i look after 21 cottages on a holiday complex mostly electrical.

Things like this but now more as a hobby

 

[James]

I worked in electronics and programming for over 40 yrs before semi retirement and now work to suit mostly repairing various radio test equipment from all over the world, for 3 days a week i look after 21 cottages on a holiday complex mostly electrical.

Things like this but now more as a hobby

Love the workshop.
I still stand by everything I have said though.
if you don’t have the info you can’t make the call for correct advice.

 

[Spoon]

You have no idea what the project is

That is correct mate. All we know is it's a place where someone has decided they want a way to isolate the power for trainees.
Why do they want this? What are the dangers that they have requested this? What level of injury could happen?
The project may just need a key switch that can isolate the power, or it may need a push button that is monitored and wired to a safety device. Only a risk assessment will answer this.

 

[Darkwood]

You are being ridiculous, you have no idea what he's switching it, maybe a spa pump for instance.

He simply asked if they did a 20 amp stop switch, and you accused me of missing the point, when in fact it was you who missed the actual question.

With all respect to the conversation, your premise of ridiculous is not founded by any of the posts, we simply do not have the info to make such accusations, if this is for course work then we don't permit direct answers only nudging but is this is real then we indeed need to question the context of his circumstances because this falls in a category that information is crucial to responses.

 

[telectrix]

a point that has been missed so far, unless i've missed it, is that a stop button is wired into the control circuit, so no way will it ever see a 20A load current.

 

[Spoon]

a point that has been missed so far, unless i've missed it, is that a stop button is wired into the control circuit, so no way will it ever see a 20A load current.

I think the OP's intensions were to use the stop button as an isolator and wire directly into the power circuit.

 

[Intoelectrics]

a point that has been missed so far, unless i've missed it, is that a stop button is wired into the control circuit, so no way will it ever see a 20A load current.

This is why the op was asked what the stop button was for and advised that its not as simple as just wiring in a "stop button". would have been just easier to search on google for the 20amp switch, than ask on this forum, if there is no intent on taking advice or explaining what the job is.

 

[mainline]

This is why the op was asked what the stop button was for and advised that its not as simple as just wiring in a "stop button". would have been just easier to search on google for the 20amp switch, than ask on this forum, if there is no intent on taking advice or explaining what the job is.

That's what the op did, he said he basically just wanted to know if a 20 amp stop switch existed, as he couldn't find one.

I get the questions being asked concerning a risk assessment, but the op a number of times said that he just wanted to know if one existed and wasn't interested in anything else.

I'm sure if he is learning in a training environment, then the trainer will put him right.

If the op returns, then maybe he can explain the scenario.

 

[Intoelectrics]

That's what the op did, he said he basically just wanted to know if a 20 amp stop switch existed, as he couldn't find one.

I get the questions being asked concerning a risk assessment, but the op a number of times said that he just wanted to know if one existed and wasn't interested in anything else.

I'm sure if he is learning in a training environment, then the trainer will put him right.

If the op returns, then maybe he can explain the scenario.

Yeah, but is an unusual request so quite rightly raised interest in what it was required for.

 

[Electro-tech]

I would use an electrical contractor, not a contactor. leave the liability to someone who knows.

 

[Spoon]

That's what the op did, he said he basically just wanted to know if a 20 amp stop switch existed, as he couldn't find one.

We understand this. But there is more to it than that.

Lets say we go with his first post.... We give him a stop button that can do 20A...
He then sticks it in his circuit and then someone comes along and says "According to table 537.4 you cant use that stop button as an isolator". He replies "But I was told I could... on a forum"

Things are rarely straight forward in our work.

I get the questions being asked concerning a risk assessment, but the op a number of times said that he just wanted to know if one existed and wasn't interested in anything else.

Again, see above.

 

[marconi]

I worked in electronics and programming for over 40 yrs before semi retirement and now work to suit mostly repairing various radio test equipment from all over the world, for 3 days a week i look after 21 cottages on a holiday complex mostly electrical.

Things like this but now more as a hobby

Dear mainline,

I gather Gibsons jigsaw company are looking for a suitable picture to continue their ‘workshop‘ category of puzzles.

Thank you for the great photos of your lab bench. It clearly is a place where work is indeed done.

Regards

Marconi

 

[mainline]

Dear mainline,

I gather Gibsons jigsaw company are looking for a suitable picture to continue their ‘workshop‘ category of puzzles.

Thank you for the great photos of your lab bench. It clearly is a place where work is indeed done.

Regards

Marconi

View attachment 99430

Thanks for the kind words

A place where work used to happen.

 

[j_arney]

Fair point, however I have never seen a training environment where the "training is wire up this spar pump"

like I said, if the risk assessment deems it suitable then go ahead but i think it is a vital step that both you and the op are missing.
OP, has anybody done a risk assessment and if so, what stop category are you trying to design. also, is a single point of failure likely to bring a risk of significant harm to anybody?

I am done with this for tonight and my final thoughts are Simpley that on the face of it neither @mainline or @j_arney have the information and knowledge required to design a suitable safety system for this project.

 

[j_arney]

Hey
Im back and done the job. In the end I had a 6amp circuit feeding the stop button then the coil and 20 amp circuit supplying a socket via a rotary isolator and contactor.
So you had a stop button and rotary isolator switching the socket on and off. I was asked to do this for a colleague at one of our sites and have no idea what he intends to do with this system. He’s designed it, he’s an engineer and I haven’t asked any questions. I can totally understand the repercussions from making mistakes in certain working environments and appreciate all the feedback. I’m on this forum to hopefully learn a bit, but sometimes there’s no need for some of the negative/ condescending replies.

 

[Darkwood]

If this is paid work and invoiced you better have a paper trail of proof to who designed it and takes responsibility otherwise it still falls at your feet, imagine is someone is injured or worse, do you expect them to put their hands up to possible dangerous installation practices or point the finger at you showing your invoice.

If you are invoicing it it would be an idea to make it part of the invoice declaring no responsibility for design or safety making it clear it was requested, this would not remove you from and possible legal action because unless you have a full paper trail to this the responsibility lies on you to assess any requests meet standards applicable, so tread carefully.

 

[timhoward]

Hey
Im back and done the job. In the end I had a 6amp circuit feeding the stop button then the coil and 20 amp circuit supplying a socket via a rotary isolator and contactor.

This is intended as a constructive comment. Where possible I would have fused down the 20 amp circuit for the coil. Then one MCB safely isolates the lot. It sounds as though you'd have to turn off two MCB's for everything at the contactor to be safely isolated?

 

[James]

Hey
Im back and done the job. In the end I had a 6amp circuit feeding the stop button then the coil and 20 amp circuit supplying a socket via a rotary isolator and contactor.
So you had a stop button and rotary isolator switching the socket on and off. I was asked to do this for a colleague at one of our sites and have no idea what he intends to do with this system. He’s designed it, he’s an engineer and I haven’t asked any questions. I can totally understand the repercussions from making mistakes in certain working environments and appreciate all the feedback. I’m on this forum to hopefully learn a bit, but sometimes there’s no need for some of the negative/ condescending replies.

I hope you have not seen my comments as either negative or condescending.
I have tried to remain professional throughout.

I presume you have used the 3 signature form to certify it.
He is responsible for design and has signed that part.
you have signed the parts for installation and for testing.

from your comment of “I have no idea what he Intends to do with the system” I can understand that you were unable to give more information so we could advise on how best to proceed.

if you were not responsible for designing the system in the first place I wonder why you asked for advice on how to get a 20A stop button when the design clearly didn’t require one.

just be absolutely certain that the certificate passes the design responsibility back to the person who gave you the design.

 

[timhoward]

I also think we need to give this guy a break. It was well worth pointing out that providing this kind of arrangement carries responsibilities, but he was given the spec, it wasn't his idea, and he's a new member.

 

[mainline]

Then one MCB safely isolates the lot. It sounds as though you'd have to turn off two MCB's for everything at the contactor to be safely isolated?

A Mcb does not provide safe isolation, especially on a TT earthing system

After all, we wouldn't want the OP thinking that It's OK to do so he could end up killing someone

I can see that James actually agreed with your post