Use Of Rcds/rcbos

[ryanm]

Hi,

Where I work there was 3 reported electrical shock accidents (all minor), and the owner of the factory would like this number to be zero which is understandable.

So, I've been given the task to count up how many RCDs/RCBOs we need to buy in to make all the circuits safer,

Some are quite obvious, as there are hanging sockets which are a potential risk as people unplug them while the machine is running etc. and the environment is damp so these do require RCDs to protect people.

But what about hard wired machines/equipment? I can't see in the regs which relates to hard wired, i.e no plug and socket if these would require an RCD. for example, a freezer, automatic doors.

Can anyone point me in the right direction please?

Thanks a lot

Ryan

 

[SLIPSHOD & SLAPDASH]

Rcds are an additional protection and should not be soley relied on to prevent shocks. It seems basic H&S is not up to scratch. It is also possible to get a shock between L & N and the Rcd will not operate. However its still good to have them and nothing wrong with protecting everything. In a situation like yours i would recommend Rcbo's so not to cause too much inconvenience if a circuit trips.

If they are being used in a damp environment you will get problems.

 

[ProDave]

As above. An RCD will NOT prevent you getting a shock.  and it will STILL hurt.

All the RCD does is limit the time so it's less likely to kill you.

So as well as fitting RCD's I think some serious H&S procedures need updating.

I would also suggest PAT testing is required.  Just unplugging a 13A plug while it's still turned on, should not give you a shock, unless the plug, socket, or cable is damaged.

 

[Doc Hudson]

Possibly some earthing and bonding may need verifying as well? What parts were people getting the shocks from?

Doc H.

 

[ryanm]

Hi, thanks for the replies.

The main issue it seems is due to wetness, as things are constantly getting cleaned with power washers, so there is a lot of spray which then gets in to the sockets. I'm in the process of trying out better IP rated sockets to try to prevent the water ingress.

In terms of H&S, the person in charge of this is looking at better proceedures.

When the shocks have occured, it is always when unplugging machiney from hanging sockets. The sockets are always live as they do not have isolators on them. Like these

http://uk.rs-online.com/web/p/industrial-power-connectors/7033767/

Thanks

 

[ProDave]

This needs a lot more looking at than just RCD's

Why do they need to keep unplugging "machinery"?  Are we talking portable tools or something more substantial?  If you are constantly hosing down then plugs and sockets don't seem approporiate

 

[ryanm]

Hi,

They are for conveyors and equipment like that. On a night they all get moved about for cleaning, and due to an enthusiastic hygiene team the plugs and sockets and everything else in the factory gets very wet. They have been told, but they say it is un-avoidable.....so I'm trying to find a better solution. Hard wiring them is isn't practical as things get moved around.

Thanks

 

[KNB]

When the shocks have occured, it is always when unplugging machiney from hanging sockets. The sockets are always live as they do not have isolators on them. Like these

http://uk.rs-online.com/web/p/industrial-power-connectors/7033767/

Is there no way of eliminating the hanging sockets and replacing with wall mounted items. You can get sockets like that mounted in enclosures with the facility for proving isolation and also protective devices locally.

Are the appliances used 240V or 415V? It's just to clarify as the picture you posted is a 3 phase plug.

 

[ProDave]

The obvious one has the be to fit an isolator switch to turn off all the hanging sockets before the night shift come in to move them.

 

[Nicky Tesla]

unplug everything before everyone finishes,  then pull the hanging sockets up out of the way on a pulley system or put them in an enclosure while cleaning.  Were is the shock,  from what to what?  The plug and socket are plastic so maybe just a H&S thing would be just to dry them off before use.

 

[Phaze]

Seems to me RCD/RCBO's will only treat the symptom, not the cause. In my humble opinion I would start with an EICR along with a full risk assessment of working practices. You will then have a starting point for your improvements.

 

[SLIPSHOD & SLAPDASH]

Seems to me RCD/RCBO's will only treat the symptom, not the cause. In my humble opinion I would start with an EICR along with a full risk assessment of working practices. You will then have a starting point for your improvements.

Wholly agree, Give that man a mince pie.

 

[NozSpark]

It sounds like the working practices there are just shocking ; )

Thought I'd get that in before Rev James

 

[Marvo]

Have a look at the Marechal range of plugs and trailing sockets. They have types that automatically isolate the supply as you unplug. There's also trailing sockets with built-in isolators. 

 

[SLIPSHOD & SLAPDASH]

Have a look at the Marechal range of plugs and trailing sockets. They have types that automatically isolate the supply as you unplug.

Dont all plugs and sockets ?  ;

 

[Nicky Tesla]

Seems to me RCD/RCBO's will only treat the symptom, not the cause. In my humble opinion I would start with an EICR along with a full risk assessment of working practices. You will then have a starting point for your improvements.

 and prob end up doing as i suggested.above..................."unplug everything before everyone finishes,  then pull the hanging sockets up out of the way on a pulley system or put them in an enclosure while cleaning.  Were is the shock,  from what to what?  The plug and socket are plastic so maybe just a H&S thing would be just to dry them off before use."

 

 

[ryanm]

Hi,

Thanks for all the replies.

We are going to fit RCDs to everything, but I have now realised even though there is suppose to be maintenance done on all the sockets (check for water/replace etc), there has never been any done (I checked the records). I didn't realise this as I am an apprentice, so don't work nights when the maintenance is scheduled for.

So as above, it is down to poor working practises! The director has got involved now, so things may change


Cheers

 

[Sidewinder]

Beware of variable speed drives on RCD's, they can give problems due to design leakage.

By your description, I would say food manufacture?

Another possibility for the shocks is static discharge remember.

Also if you are to fit RCD's then remember they spare not fit & forget, and not the real final solution.

The advice given above is all sound IMHO.

 

[poni]

http://uk.rs-online.com/web/p/industrial-power-connectors/7209437/

http://uk.rs-online.com/web/p/industrial-interlocks/4925925/

you could use this type of plug and socket and upgrade the bonding

or use a earth monitoring system that would cut the supply when the plug is removed

you can get plugs with an extra (short) pin for this

 

[boltonsparky]

Too much reliance is put on RCDs these days, they are lifesavers and should be used but only relied on once all other methods of preventing electric shock have been exercised....don't forget they can and sometimes do fail to operate within the safe time limits.

Fitting RCDs to everything is going to cause you a lot of nuisance tripping unless they come up with a better solution to their current cleaning methods. Glad the directors have got involved before someone gets seriously shocked.

The best prevention of electric shock occurring in the first place is common sense.