EM Stop Buttons

[gaulty]

It's been awhile!

need a little help on how to wire 4 Em stop buttons for Four work bays at a college through a contactor so if I hit any of the stop buttons it would knock off all four.

contactor would be normally closed, it's just wiring back through the coil I'm not too sure on. You would be lucky if there's 13Amp in total for all the bays.

my idea was to take put each bay on its own cct, wire from breaker to contactor and contactor to bays and have coil through em stop but how do I wire coil so that if I hit any stop button it opens contactor.

my original idea was to have a stop for each bay which only did that bay but client isn't wanting that, he want any stop button to kill power to them all

 

[telectrix]

what are the bay supplies? 3 phase or 1 phase?

 

[Bobster]

What's your college instructor say?

 

[Leesparkykent]

What's your college instructor say?

His profile says he's approved.

 

[Bobster]

His profile says he's approved.

Oh dear...

 

[Richard Burns]

Wire your power off buttons in series to the coil.

 

[telectrix]

His profile says he's approved.

so was the school i attended for 4 years.

 

[Pete999]

Is it 4 separate circuits or just 1? Sorry didn't see the bit in your post saying 13 A total, so one circuit then yes? N/C contactor supplied from it's own OCPD or looped off of the live in the contactor in series with a stop button through a line type fuse of the appropriate size, power goes off contactor goes O/C fail safe same as if someone hits the stop button.

 

[dansk]

Would it not be best using Normally Open contacter? And wire the ES buttons on a ring?

 

[davesparks]

Would it not be best using Normally Open contacter? And wire the ES buttons on a ring?

Yes a normally open contactor should be used to give fail safe operation.
Stop buttons should be wired in series. I can see what you mean by calling it a ring, but that could cause confusion with a normal ring circuit and end up with someone wiring them in paralell.

 

[Pete999]

Would it not be best using Normally Open contacter? And wire the ES buttons on a ring?

Yes I suppose it would and careful consideration, my initial post saying N/C would be fail safe is wrong.

 

[netblindpaul]

You must undertake this work in accordance with BS4163 as it is a Code of Practice for educational workshops basically.

 

[UKMeterman]

Also have a read of BS EN 13850

 

[Darkwood]

Many requirements here the OP hasn't even considered and as others have expressed with relevent BS regs means you cannot just design a functional circuit without knowledge of these requirements, as this set-up will be classed as a safety critical system you need to be sure you know what your doing, I did one many years ago before there were any real regulation and guidelines and I design it to a standard that i bet would still pass modern guidelines.

- It will require to be fail-safe however the design is done
- I assume there will be some requirements for key reset system so only a keyholder ( e.g tutor or trained assistant) has the capability of energising the bays.
- Dependent on the nature of the hazards their may be requirement for alternative E-stop actuators like a foot or push bar.
- Consideration will be needed for equipment that may be a hazard if suddenly energised but I'll be surprised if such equipment will be been used in the college to start with.


-

 

[netblindpaul]

Basically DW 4163 is the "c type" standard for this type of install, iykwim.
This will lead you to the other standards and requirements.

 

[gaulty]

As I said it's been awhile!

Thanks to those who have left helpful comments!

It's just CompEx training bays not much in them as such. 1 light and a switch everything else is dead. Bays need to be hooked up through a stop button wasn't 100% how to wire it through contactor.

as I said thanks again to those who have helped

 

[jamie-spark]

Not really as dark wood and netblind have said a safety circuit or reset should be used. I have seen a college power DB controlled by a main contactor ( before the main switch ) and 4x crap RAAS key to release E STOPS. Every night the lecturer bangs in estop 1 in to isolate the power. The estop contact had failed and would only stay open when continually pushed in.

 

[Darkwood]

Basically DW 4163 is the "c type" standard for this type of install, iykwim.
This will lead you to the other standards and requirements.

Had a quick scan through that and nothing really directly relative to E-stop set ups but does have a generalisation on requirements of different harzards in and around the school workshop.. never really needed to know it as I stopped doing that kind of work a few decades ago. PS had to look up iykwm ...tbh never seen that one lol

 

[netblindpaul]

DW, it doesn't call them emergency stops per se, look @ 5.2.5.

 

[Darkwood]

DW, it doesn't call them emergency stops per se, look @ 5.2.5.

Cheers ... think I scanned too quickly but it really only touches on the subject and basically tells you any system should be designed to comply with BS 60204 - 1 and BS 7671 and just excempts the requirement for the system in staff prep' areas I was expecting a more indepth set of reg's but it's just there to direct you out of the BS4163. In reflection then you kind of treat the E-stop system in the student bays as you would for a machine and apply the same logic with a risk assessment etc before designing it.

It looks like BS EN 13850 as pointed out earlier is the one that gives the principles of design of the actual E-stop system but doesn't deal with aspects like motion stopping, braking shielding etc and just gives the basic underlying principles itself as well as addressing liability.

So to reflect here, it is understandable why this area can be got so wrong as you really need to have a working knowledge of the:-

-BS60204-1
-BS 13850

You need to ensure there are no requirements that are addressed in the:-

-BS 4163

And finally a working knowledge as you would hopefully be already compliant to:-

-BS 7671

Or your arse is on the line for any accident/death arising from poor design which has compromised other safety systems or has failed to activate due to component failure (not fail safe) with the exception of user negligence e.g. a broken actuators (E-stops) that had not been addressed by the school/college on their routine inspection and testing of the system.

 

[netblindpaul]

Your points are a lot of the issues.
"People" get asked to wire things up, so, they do.
They forget that without the design detail, when they wire them, they become the designer.
So, they have ALL of the duties of the designer of what ever system they wire.
Safety or otherwise.
Now under BS7671, this is not so bad, because the design is detailed in the standard and the supporting documents, and it is pretty simple really.
However once you move away from this into FA, EM Ltg, machinery, safety systems etc. then it gets complex and expensive really quick, because you must have all of the relevant standards & be able to prove that you can work to them, along with suitable insurance unless you are a mug,

 

[Darkwood]

I believe that training and college courses have a lot to answer for too. I think they should introduce lessons in areas of the industry they should not get involved with and make them fully aware why and the possible concequences... just added a few new firms to my customer base and what I come across from basic sparkies trying to look like the Electrical Engineer is very scary indeed...even basic industrial install is been messed up and I'm sick of seeing S/Y replacing many wiring set ups its just not designed for and to top it the screen is never earthed. Just seen a factory with 20plus S/Y's from 3ph submain to various machinery - run across the tiles in a false ceiling and this install is still going on (well not for long when I bring it up) but does sound like it was the cheapest quote so they chose him....it beggars belief :nuke::uhoh2:

 

[shanky887614]

I believe that training and college courses have a lot to answer for too. I think they should introduce lessons in areas of the industry they should not get involved with and make them fully aware why and the possible concequences... just added a few new firms to my customer base and what I come across from basic sparkies trying to look like the Electrical Engineer is very scary indeed...even basic industrial install is been messed up and I'm sick of seeing S/Y replacing many wiring set ups its just not designed for and to top it the screen is never earthed. Just seen a factory with 20plus S/Y's from 3ph submain to various machinery - run across the tiles in a false ceiling and this install is still going on (well not for long when I bring it up) but does sound like it was the cheapest quote so they chose him....it beggars belief :nuke::uhoh2:

you get what you pay for, we tend to use sy in trunking because of its lack of strength (we would use yy instead otherwise) to be honest this is to the designer spec, depending on route etc we might use swa instead

 

[Aindowsimon]

Cheers ... think I scanned too quickly but it really only touches on the subject and basically tells you any system should be designed to comply with BS 60204 - 1 and BS 7671 and just excempts the requirement for the system in staff prep' areas I was expecting a more indepth set of reg's but it's just there to direct you out of the BS4163. In reflection then you kind of treat the E-stop system in the student bays as you would for a machine and apply the same logic with a risk assessment etc before designing it.

It looks like BS EN 13850 as pointed out earlier is the one that gives the principles of design of the actual E-stop system but doesn't deal with aspects like motion stopping, braking shielding etc and just gives the basic underlying principles itself as well as addressing liability.

So to reflect here, it is understandable why this area can be got so wrong as you really need to have a working knowledge of the:-

-BS60204-1
-BS 13850

You need to ensure there are no requirements that are addressed in the:-

-BS 4163

And finally a working knowledge as you would hopefully be already compliant to:-

-BS 7671

Or your arse is on the line for any accident/death arising from poor design which has compromised other safety systems or has failed to activate due to component failure (not fail safe) with the exception of user negligence e.g. a broken actuators (E-stops) that had not been addressed by the school/college on their routine inspection and testing of the system.

It's scandalous the cost of those bs books ! Like an electrician doesn't have enough ridiculously overpriced books he can spend his money on
I want to be the best , safest electrician , compliant I can

Gn1-8£ 30 each!
Regs £100
Guide £30
Bs 13850£108

And goes on ....

I'm employed and do my best to keep up but they are royally extracting my waste liquid , they should be free !

And a son to feed to boot

 

[Darkwood]

I agree on the cost but dont think free is the solution as it would habe any tom dick or harry trying to move into areas they are clearly not competent in, what should be in place is a reduced cost for those that can provide relevent certification of you competence to limit certain rogues from jumping into safety critical designs... if you treat these regs like the holy book it shows that in the wrong hands its often mis-interpreted and then we have people getting killed. We have to somehow limit access to credited companies only Imho

 

[Aindowsimon]

In my head I ment free for us , as electricians obviously, and not handed out like a pamphlet , for the reasons you highlighted . Just the way I see it maybe one allocated per tradesman and if lost would be replaced at cost seems fair to me ,
Not charging a days wage per book to provide us the information so we can make our work compliant

 

[shanky887614]

In my head I ment free for us , as electricians obviously, and not handed out like a pamphlet , for the reasons you highlighted . Just the way I see it maybe one allocated per tradesman and if lost would be replaced at cost seems fair to me ,
Not charging a days wage per book to provide us the information so we can make our work compliant

i wouldnt mind paying if they brought it out in ring binder form and changed it to be more like the nec in usa, any aditions have to be avalible loose leaf and can be slotted into the book and if any regs change just the affected pages need to be changed

(the nec code numbers are the same throughout revisions)

but the cost is a con, 60-100 per revision with very few changes.

honestly what has changed since red book? not much really lets be honest

 

[Bobster]

Don't see why .pdf copies couldn't be made cheaper than they are.

The company gets a discount for being a member with them, that's a bloody rip off. We need it to trade though, I've seen what happens to small companies who wing jobs involving machinery safety etc... They don't stop in business much longer after the court hearing.

 

[davesparks]

Building regulations are a free download
HSE documents are normally a free download
British standards are a ridiculously expensive download.

 

[jamie-spark]

I can't quite remember the exact costs , but I think it was 300 plus vat for the IET SILVER package. It gets you gn 1 to 8, BS7671,OSG, GUIDE TO THE BUILDING REGS and calculations for electricians book. This gives you for 4 licences, 2 for PC 2 for tablets . if 4 of you chip in you could get all this for under 100 quid each. Although 1 person would have control of the account details and only BS7671 has been updated online so far

 

[netblindpaul]

To be honest from what I have heard, the IET online package is really bad.
My experience to date with it is not good.
There are a few complaining about it on the IET.
The regs, osg, & gn's are all updated to the byb though.
Mind none of that content is any use for machinery systems.