Quick question - would a dead mans switch (DMS) be sufficient (basically it would just be that the person let go of the control) or do i need to get an additional e stop. Searched for answer and was going with DMS sufficient however concerned that in emergency occassionally people grip to whatever they are holding so do i need E Stop?? Got to the point I am going round in circles. Any advice most appreciated. Thank you

Shaz A little more info n the equipment/hazards may help people advise you on this. I suspect there are situations that require one or other of these devises and some which require both - dare I say it what does your risk assessment say? Brian

I would say go for the estop as well. What if, for whatever reason, the operator was unable to let go of the DMS?? Or it got stuck or some idiot wired it shut?

thanks for all your advice I have contacted the manufacturer to seek their advice for the machine in question and they have said that a seperate e stop should not be put in place in addition to the DMS as it interferes with the braking system. The DMS is enough to stop it due to where it is located, etc. They did say that they have whole workshops connected to 1 e stop however this is not possible in the workshop we have or with the equipment we operate. Thanks again Shaz

Shaz Sorry we were obviously drafting our post at the same time, it was only after I hit Post that I saw you had consulted the manufacturer. Brian

Someone has confused emergency stopping and emergency switching? Please refer to Part 2 BS7671:2008 as amended. Zimmy

I have experience (albeit with different type of equipment) whereby the worker secured the DMS with wire so he didn't have to hold it down. If the person had an accident or something went wrong then someone else should be able to switch the machinery off i.e. Big red button. Obviously they shouldn't be using the wire to hold to DMS down but that's a different subject altogether.

zimmy, It could be argued, successfully I believe that BS7671 does not apply if you check the definitions then it precludes itself from applying to machinery, the relevant standard referred to in the HSE ACOP on PUWER98 is BS EN 60204-1 this is currently in Amd dated 2009 IIRC, mine is not here. All, IMHO, IF the machine is CE marked then you should not modify it without re- CE marking it as a one off, else you can never comply with PUWER98 requirements. If the machine relies on dc injection braking then you must not remove the mains electric supply when stopping the machine. The best I can point you in the direction of for examples is central emergency switching systems in school class rooms, these are under BS4163, not relevant here, however, these e-stop rings that cut power to all of the machines are required in this environment, however, there is a published HSE document and in the text of 4163, that dc injection braking and central switching are an excluded combination. So, unless you know how the machine is braked then you should not modify the supply circuit to remove power. If you can't post the machine make and model then please PM and I will ask the manufacturers again, as I have close links with many of the wood machine manufacturers and importers (agents) in the UK. If the machine is not braked then if there is possible access to the tool during run down then as I understand it your risk assessment should show that braking is required and by now it should be fitted as the change over time has elapsed. If the machine is not dc braked then it may have an electro magnetic brake which brakes automatically on being de-energised, so on release of the hold to run button the machine will brake to a halt. The other possibility is that the machine is designed with such drag that it inherently stops within the requirements of the standards. I would caution you very politely on believing what your electricians say as there will be many who will not be trained in the requirements of machinery electrical safety if they are installation electricians working to BS7671 as this does not cover machinery, see above. You can even defeat the big red button if you try all machinery and guarding can be defeated, that is down to management control. Without understanding more about the machine and the physical install I feel that it is difficult to say any more. How far should this be taken, remember power tools are hold to run switches, pistol drills, angle grinders, chop saws, sanders, jigsaws etc. these are not fitted with emergency stops.