415v 3 phase sockets and rcd protection.

[simpson93]

Afternoon all,

Looking for a little guidance, other than doing sub mains in armoured I don’t do much three phase work.

I’m looking to install some final
Circuits for some three phase cooking equipment but I find myself stuck on a few things, as the sockets will be over 16amp they will need to be rcd protected but I can’t seem to find anything to find a Hager board rcbo etc. What’s the best way to protect it?

Also generally if doing a three phase sub main I would take an additional earth as I’m not so keen on solely relying on the armoured earth. Do most people generally rely on the armoured earth or use 5core?

Thanks for your help

 

[Nigel]

I wan’t aware that stating facts was rude?

Carry on then.

 

[davesparks]

Why are people so dead set against having RCD protection fitted to these socket outlets?

 

[davesparks]

I’m not disputing the need for a plug and socket only the need for RCD protection..
Up until now equipment in this environment hasn’t needed to be considered for RCD protection..

Over the years there have been many things which have changed in the regulations resulting in this same type of situation. Something now needs to be done differently to how it used to be done, why not accept the change as a chance to improve safety rather than fighting against it?

People reacted the same way when RCDs became a requirement for all general purpose socket outlets regardless of whether they could be used outside or not, now everyone just accepts it as the norm. In a couple of years time the general consensus will change and this situation will be accepted as the norm.

 

[BrendonP]

The purpose of A Risk Assessment is to identify potential risks and hazards. Then put in place measures to minimise each of the risk’s.

In this case we would have to identifying if there is a risks of HAVING the RCD in circuit in order for there to be a risk reduction in omitting the RCD.

 

[BrendonP]

Why are people so dead set against having RCD protection fitted to these socket outlets?

There are very specific circumstances where the 30ma RCD can cause genuine problems. One i deal with regularly is sockets to supply temporary electrical distribution for entertainment ie sound and lighting for festivals. The overall earth leakage of the connected equipment can add up fast without being near 32amp load. These sockets generally connect to portable power distribution that has individual rcbo’s on each circuit. The original proposal to rase the requirements for rcd’s to 63amp where thankfully dropped.

But this is way off topic. Apologies.

 

[davesparks]

There are very specific circumstances where the 30ma RCD can cause genuine problems. One i deal with regularly is sockets to supply temporary electrical distribution for entertainment ie sound and lighting for festivals. The overall earth leakage of the connected equipment can add up fast without being near 32amp load. These sockets generally connect to portable power distribution that has individual rcbo’s on each circuit. The original proposal to rase the requirements for rcd’s to 63amp where thankfully dropped.

But this is way off topic. Apologies.

I work in the same area, theatre and outdoor events. 30mA RCDs don't cause problems, the inappropriate use of them causes the problems.

I can't say I've ever had a problem providing 30mA RCD protection to final circuits.
Problems only happen when people do stupid things like putting distribution circuits on 30mA RCD.

 

[BrendonP]

I work in the same area, theatre and outdoor events. 30mA RCDs don't cause problems, the inappropriate use of them causes the problems.

I can't say I've ever had a problem providing 30mA RCD protection to final circuits.
Problems only happen when people do stupid things like putting distribution circuits on 30mA RCD.

Yes exactly. Im talking about the supply socket for the distribution to connect to.

 

[DPG]

As Dave said above, why are people trying to avoid having an RCD on these sockets. What problem do you foresee if they are RCD protected?

 

[SparkyAndGeorge]

Simple really. Either fit an RCD or the designer conducts a risk assessment, bearing in mind they will have to justify their decision that RCD protection was not necessary, possibly in a court of law, especially if someone was killed or injured as a result of the RCD protection being omitted.

 

[Nigel]

Why are people so dead set against having RCD protection fitted to these socket outlets?

Not dead against. Just accepting that they are not always required and are not always necessary.

For example we install 32A TP+N sockets for retail kiosks on stations. We do not install these on RCDs as they will ultimately be distribution circuits so our risk assessment will insist that the kiosk will have all circuits independently protected by RCDs.

 

[davesparks]

Yes exactly. Im talking about the supply socket for the distribution to connect to.

Which is normally somewhat larger than 32 or 63A!

 

[Deleted member 26818]

Not dead against. Just accepting that they are not always required and are not always necessary.

For example we install 32A TP+N sockets for retail kiosks on stations. We do not install these on RCDs as they will ultimately be distribution circuits so our risk assessment will insist that the kiosk will have all circuits independently protected by RCDs.

Are you telling us that you get such RAs accepted by National Rail and TFL?

 

[Nigel]

Are you telling us that you get such RAs accepted by National Rail and TFL?

Yes. Of course.

 

[The_apprentice2.0]

I do enjoy this forum

 

[Norah Nabino]

? But socket outlets up to 32amp require RCD protection. Or is there a way around this ?

Yep,that is the right way.

 

[Norah Nabino]

I suggest you read back through the thread from the start!
I have only given constructive advice!
Please prove otherwise..
I have been involved in the installation and repair of commercial catering equipment for 25 years, I am an approved engineer for many brands.
What has been suggested is totally unnecessary..
just because you can’t do something doesn’t mean that it can’t be done, a risk assessment in this instance would be easy enough..
It’s stationary equipment that doesn’t need RCD protection

Are you sure about what you are saying here??
Are you uo to date with BS7671???

 

[Norah Nabino]

I suggest you read back through the thread from the start!
I have only given constructive advice!
Please prove otherwise..
I have been involved in the installation and repair of commercial catering equipment for 25 years, I am an approved engineer for many brands.
What has been suggested is totally unnecessary..
just because you can’t do something doesn’t mean that it can’t be done, a risk assessment in this instance would be easy enough..
It’s stationary equipment that doesn’t need RCD protection

Are you sure about what you are saying here??
Are you uo to date with BS7671???

 

[Norah Nabino]

I’m not disputing the need for a plug and socket only the need for RCD protection..
Up until now equipment in this environment hasn’t needed to be considered for RCD protection..

You need to read the regulation 411.3.3.

 

[Norah Nabino]

I’m not disputing the need for a plug and socket only the need for RCD protection..
Up until now equipment in this environment hasn’t needed to be considered for RCD protection..

You need to read the regulation 411.3.3.

 

[Norah Nabino]

How can you guarantee that the person unplugging the equipment will be instructed?
How can you guarantee that the equipment will always be plugged back into the same socket-outlet?
What difference would it make whether the equipment is or isn’t plugged back into the same socket anyway?

Exactly

 

[Nigel]

Are you sure about what you are saying here??
Are you uo to date with BS7671???

Are you?

 

[Norah Nabino]

Are you?

Of course.

 

[bernie4253]

I got bored with all the cat fighting and haven't read the entire thread, so forgive me if I've said something that has already been said.

If you decide RCD is the way to go, Hager do a range of three-phase RCD's. They are not cheap, but you can often find them on ebay.fr second hand. There is nothing wrong with them. They are usually from domestice installations in the rural areas which are often three-phase and some UK sparkies change them to single-phase so the RCD's are just surplus. Search for "Hager differentiel tetra"

 

[Charlie_]

Hi Norah
Thanks for the advice on reading the regs..
In a commercial kitchen where would you put a 3 phase RCD protected socket to protect a piece of stationary equipment; such as say a twin deep fat fryer or a 20 grid combi oven?
That little book you hold so dear hasn’t got all the answers, what will you do now?

 

[Toneyz]

I’m not disputing the need for a plug and socket only the need for RCD protection..
Up until now equipment in this environment hasn’t needed to be considered for RCD protection..

Yes, but this all changed with the 18th.

 

[Ruairi Hansen]

Install a 32A 3 phase rotary switch instead?

 

[EalingBadger]

Given the propensity of electric heating elements inside catering equipment to break down to earth I would want to fit RCD protection regardless. Better that (and an annoyed customer as the RCD starts tripping intermittently in the future!) than the black mess that will result from the circuit not disconnecting until the MCB pops.

 

[Charlie_]

Satisfactory Zs readings would be an essential requirement of any RA

 

[Toneyz]

Install a 32A 3 phase rotary switch instead?

Whilst this would be ideal so not having a socket neglects the need for RCD protection, the OP has stated that he is required to provide si=ockets.