My Myford ML10 instructions show the 4 conductors from the Dewhurst Drum Type Reversing Switch going to the starting and running windings of a single phase motor (or for TP, 3 wires to the motor from a different combo of pins on the switch).

PS - does anyone on this forum NOT own a lathe?

Broadly agreeing with many of the above, I would put a 60309 socket-outlet on the wall at which point BS7671 stops. Then, if the lathe is intact and operational, one option might be to put a plug on it, test it electrically and return it unmodified with a written note to the owner that the scope of work is limited to testing for electrical faults. The owner could then conduct their own risk-assessment of the suitability of the machine in its original configuration, and if necessary commission a safety upgrade as a separate job, perhaps to the specification of someone familiar with the requirerments of the M(S)R. The latter would also be a solution if there is no NVR at present and the owner wants one.

If the electrics are faulty it might be acceptable to repair using equivalent parts, without incurring additional liability for any design element, again subject to the understanding of the owner that no alteration or improvements over the original specification have been made. OTOH I agree that the original Dewhurst and Craig & Derricott drum switches soldier on for decades, possibly centuries. The forward / reverse switch on our 54-year old forklift (which admittedly only switches a 24V control circuit) still clicks back and forth reliably even though the control knob itself is wearing away.

It is a 0.55kW APPLIANCE, so a plug is perfectly fine,perhaps with a 3A fuse

Being a 0.75hp motor in old money. I suspect a typo here as a 3A fuse would soon be defused by the likely 25A or so of starting current. A 13A fuse would be OK if it ends up on a BS1363.

E2A I don't own a lathe, and don't need to as there is a good selection at work. No, wait, how could I miss that huge blue thing in the corner. I do own a lathe, It's a 1979 Mazak Dynaturn with Fanuc 5T control - still running from paper tape on an 8088 CPU.

So the machine could run through a no Volt release type direct on line starter then?

Z.

Well given that it's a home workshop, technically BS 7671 doesn't allow unshuttered 60309 socket-outlets (553.1.201). I suppose you could argue that using one which has an interlock compiles with the spirit, if not the letter, of the regs.

wallywombat said:

I suppose you could argue that using one which has an interlock compiles with the spirit, if not the letter, of the regs.

How?

I understand the argument being that the plug can't be removed with the supply switched on ... which would,I guess, be OK  on the basis of 'no less safe' if you were looking to depart from Reg 553.1.201, but only if the switch were an isolator (providing isolation of socket-outlet tubes from the mains instead of internal shutters).

But there's a problem ... whilst BS EN 60309-4 does cover products that have either an interlocked switch or an interlocked isolator, a device with an actual switch suitable for isolation must be marked with one of the isolation symbols (see notes to Table 537.4 of BS 7671 for examples) ... and whilst I've seen loads of BS EN 60309-4 outlets, I've never seen one marked suitable for isolation.

Hence, I can't see how it offers equivalent safety to a shuttered outlet, especially in dwellings where there may be children ('no children now' doesn't mean 'never children there ever').

PS - if anyone has come across a BS EN 60309-4 socket-outlet with a switch that is suitable for isolation (and suitably marked in accordance with BS EN 60309-4 for that purpose), please let me know.

There is no reason at all why a BS 1363 plug and socket should not be used. However, it is debatable whether a workshop is "household or similar premises". Most households do not have a lathe or other machine tools. 

Chris Pearson said:

However, it is debatable whether a workshop is "household or similar premises".

Not a debate that we can resolve, though ... would require legal professionals to determine what is within the curtilage of a dwelling (e.g. see https://www.bidwells.co.uk/what-we-think/what-is-curtilage/ ) and then whether the intent of Regulation 553.1.201 actually covers it.

This is tricky, as 553.1.201 states 'for household and similar use'. Household involves the people not just the place, so if it's in the curtilage, and intended for use by someone who is a member of the household ... it's potentially 'household and similar use' ?

But then again, it's possible to run a business from some (but not all) homes, depending on deeds and covenants ...

Reading 553.1.201 literally, I'm drawn to the ambiguity of the word 'use'; household and similar location vs. household and similar application. Pragmatically, it is referring to the means by which users connect everyday appliances in locations with typical risks and environmental factors. Conversely, I have transportable machinery and devices in my house that consume currents much to high for BS1363; they are not used for business but nor are they typical of domestic appliances.

Anyway, I didn't want to drag the thread off topic by mention of an alternative to BS1363 which I agree is suitable for this lathe, but I found the points raised interesting because I don't get involved with domestic installations.

Most households do not have a lathe or other machine tools. 

Maybe not, but in my close circle it is the majority - rather like doing DIY and repairing your own car, such things tend to go in family and friend group  clusters,. Part of the problem is that we on this forum are likely to be members of that group - I also have a pillar drill, an arc welder, an amateur radio license and associated kit, and an unusually complex IT set up. It is no dafter than a neighbour with her really fancy kitchen.

In any case we need to be able to handle the cases that do, if they are outliers or not, there are enough that they deserve consideration. Not everyone is a passive consumer.
Mike.

Lucien Nunes said:

Pragmatically, it is referring to the means by which users connect everyday appliances in locations with typical risks and environmental factors.

That's an interpretation ... as I said, only a court can decide, hopefully that won't be after a child or vulnerable person has poked something into the outlet.

But I'm not 100 % sure I'm with you on the word 'use'.

Let's take a step back and think about the wider context here, based on the example of 'poking things into the outlet. Workplaces have legal duties for risk assessments and appropriate safety controls - and employers are vicariously liable for the acts or omissions of their employees. Those provisions are somewhat absent in homes, although the homeowner still has duties of care. So is it possible the real intent of the protection is not necessarily related to the 'use', or really not just the 'user', but 'people in the premises as a whole', who might be impacted if the shutters weren't there?