559.9 Stroboscopic Effects

[PC Electrics]

I've been asked to carry out a PIR on a small woodwork workshop.

The workshop has various fixed woodworking machinery, some with exposed rotating components.

The lighting is standard fluorescent on a single phase, so no account has been taken of the danger from strobe effects.

Would you code this as a 2 or 4?

And would you recommend HF fittings to alleviate the problem?

Ta, PC

 

[ianmacd]

Difficult one. There is nothing Electrically unsafe with this so maybe a code 4.

 

[Lee321]

correct but the enviroment could be deemed unsafe if a rotating wheel appears stationary

 

[ianmacd]

Yes for new installs but if its existing......

 

[Andy™]

do any of the machines have an inbuilt filiment type lamp? or are there any near?

if not, id go with 4

cant really give 2, as the electrical installation is safe, its the other equipmet that isnt

 

[Lee321]

a chopped off finger is a chopped off finger wether the job is new or existing

 

[ianmacd]

But it was not caused by the electrical system was it?

 

[Lee321]

indirectly if the the electrical lighting was off or designed correctly the finger would still be on :x

 

[Apache]

I have a woodworking lathe and fluorescent lights. An all the speeds my lathe will go I have never experienced the stroboscopic effect.

 

[Lee321]

I have a woodworking lathe and fluorescent lights. An all the speeds my lathe will go I have never experienced the stroboscopic effect.

its not a myth patch :coat :x

https://www.youtube.com/embed/ZHs563TxkeI?feature=oembed

 

[ProDave]

I would look at the machinery from a EN60204 (machinery directive) point of view, not wiring regs.

Look to see if guarding, interlocking and emergency stops are up to scratch.

We all know machinery like saws, lathes, drills etc unavoidably have rotating parts which is why emergency stops should be provided and guarding where possible. It's also why they should only be used by skilled trained operatives.

But if things like belts, gears, motors etc are ungarded, they need to be enclosed. There is no operational reason for them to be left exposed. The only bits that should be exposed are the actual things you are working with, i.e the chuck on a lathe or drill. Even then, some guarding should prevent direct access when in use.

I really don't think anyone is going to THINK a machine is stationary when it's not due to strobe effects. If they do, then IMO they are not sufficiently skilled to be touvhing the machine in the first place.

 

[ianmacd]

No, it would need to be going a multiple of 50Hz to appear stationary.

 

[Sidewinder]

Patch is correct as are the rest of you.

You have to hit the exact stroboscopic speed for the spindle to appear stationary.

I would say a 3 or 4 at worst.

Not a 2, be careful as you could end up straying into areas that are not BS7671.

For example the machinery does not come under 7671, but HASAWA, EAWR & PUWER, with 60204-1 being one of the standards.

You can comment only on this I feel.

If you stray from 7671 then you could be open to criticism for not inspecting the machines to PWUER98 thus 60204-1 requirements, where would it stop?

I say it stops with 7671.

 

[ProDave]

[quote name='Lee

 

[ianmacd]

Also, what then seperates you from the plumber who is moaning about your gas bond?

 

[Lee321]

yes dave we are switched on enough but simple ppl are not so

 

[Lee321]

intresting that some have said its not OUR problem.

whilst i would agree about guards etc these are there for say someone falling into the machines

why would regs mention it if we are to say well the machine needs protecting

not under our scope

 

[ProDave]

[quote name='Lee

 

[Lee321]

yeah pretty much as i said but only mega short version lol

so in this day and age of machine to person injury safe guards is OUR obiligation to strobscopic effects negated and need not be concidered?

i think not. ??

the thread isn't about machine protection its about SE regardless of impeccable machine guarding etc

 

[Risteard]

You could say that the installation is inappropriate for its environment. I think it could potentially be a Code 1 deviation.

HF lighting or connected to alternate phases would fix this.