RCD protection on 3 phase sockets/18th edition

[leep82]

Ive recently watched some short online videos from the NICEIC which talks about some of the changes that will be incorporated in the 18th edition. One of these changes i think says that all socket outlets upto 32a will require RCD protection.

I have recently been to look at a job where the customer requires 2 x 3 phase supplies ( 1 x 16a and 1 x 32a ). Both supplies will be via commando socket outlets for a dedicated piece of equipment. I seem to remember that when the latest ammendment was introduced there were certain dates that you could install upto, ( e.g insulated consumer units in domestic premises were ok upto said date or ongoing jobs started prior to the date could continue to be installed to the pre ammendment standard, hopefully ive understood that correctly).

My question now is regarding the job i will hopefully be undertaking and whether to provide RCD protection or not. Obviously we are still working to the 17th edition but is it worth thinking ahead and ensuring that my install is still compliant in the months to come?

 

[davesparks]

The 16A socket may well require RCD protection under the current regulations.

You carry out the installation in accordance with the regulations under which it was designed, so if you are designing it now and producing suitable paperwork as such then you install it according to that design.

The draft of the 18th is just that, a draft, it can and will change before being finalised and published.

 

[leep82]

The 16A socket may well require RCD protection under the current regulations.

You carry out the installation in accordance with the regulations under which it was designed, so if you are designing it now and producing suitable paperwork as such then you install it according to that design.

The draft of the 18th is just that, a draft, it can and will change before being finalised and published.

The 16A socket may well require RCD protection under the current regulations.

You carry out the installation in accordance with the regulations under which it was designed, so if you are designing it now and producing suitable paperwork as such then you install it according to that design.

The draft of the 18th is just that, a draft, it can and will change before being finalised and published.

Would the 16a commando require RCD protection even though its not intended for general use or use by ordinary persons?

 

[davesparks]

Would the 16a commando require RCD protection even though its not intended for general use or use by ordinary persons?

I have no knowledge of the installation so can't really comment.
If it is dedicated and restricted to a specific piece of equipment then it may not require it.

 

[leep82]

I have no knowledge of the installation so can't really comment.
If it is dedicated and restricted to a specific piece of equipment then it may not require it.

The little information that i have been given is that the supplies are for a welder and table saw, so certainly dedicated pieces of equipment. I intend to use SWA to supply both items which will clipped to purling/girders, so no RCD protection needed for my install method. Only the trained staff at the premises will be using the machines so is protection by an RCD as a means of additional protection necessary?

 

[davesparks]

The little information that i have been given is that the supplies are for a welder and table saw, so certainly dedicated pieces of equipment. I intend to use SWA to supply both items which will clipped to purling/girders, so no RCD protection needed for my install method. Only the trained staff at the premises will be using the machines so is protection by an RCD as a means of additional protection necessary?

As the installation's designer you must make that decision.
Personally I have not installed a TP table saw on a plug and socket before, they have always been hard wired to an isolator. Being on a plug and socket implies that it is a portable appliance.

I very much doubt that either socket will require RCD protection, but I won't accept the liability of making the decision unless I am being paid to do so.

 

[leep82]

A few pics of the finished install for those interested. In the end i opted to not provide the 16a commando socket with RCD protection. I now have to provide a risk assesment as to why, which im struggling with a little so anybody who can point me in the right direction would be most grateful. Is there any templates out there specifically for this and if so what should it include. Thanks

 

[leep82]

 

[davesparks]

A few pics of the finished install for those interested. In the end i opted to not provide the 16a commando socket with RCD protection. I now have to provide a risk assesment as to why, which im struggling with a little so anybody who can point me in the right direction would be most grateful. Is there any templates out there specifically for this and if so what should it include. Thanks

Surely you must have done the risk assessment to establish that RCD protection could be omitted?
You can't just opt out of fitting and RCD and make up the papaerwork later.

 

[Stspark]

Haven't ever seen templates.
A few points to consider though, for dedicated regularly maintained pat tested appliance, user to be a trained and competent operator of the appliance.

Could you of not easily installed a local rcd enclosure above the outlets?

Also the duty holder should perhaps be the person completing the risk assessment?

 

[leep82]

Surely you must have done the risk assessment to establish that RCD protection could be omitted?
You can't just opt out of fitting and RCD and make up the papaerwork later.

Only in as much as taking things into consideration such as the type of wiring, and that only skilled persons will be using the machinery. It was a decision i made after a discussion with the person ordering the work and prior to starting any work. I use the iCertifi app for my test results and when you get to the end of the certificate there is a specific section where a risk assesment for the omission of RCD's can be included, so it was always going to be provided on completion of the job along with the test results.

 

[davesparks]

Only in as much as taking things into consideration such as the type of wiring, and that only skilled persons will be using the machinery. It was a decision i made after a discussion with the person ordering the work and prior to starting any work. I

How have you ensured that only electrically skilled persons will be using the machinery? Someone could be a highly skilled welder and yet have no ability to identify a piece of equipment which has deteriorated electrically.

 

[leep82]

How have you ensured that only electrically skilled persons will be using the machinery? Someone could be a highly skilled welder and yet have no ability to identify a piece of equipment which has deteriorated electrically.

I havnt, and if i should have then i have misinterpreted the term skilled persons. I assumed a skilled person would be sombody operating the machine who was familiar with it. How would you go about ensuring only electrically skilled persons used such equipment?

 

[Wilko]

How have you ensured that only electrically skilled persons will be using the machinery? Someone could be a highly skilled welder and yet have no ability to identify a piece of equipment which has deteriorated electrically.

I agree Dave. While there are exemptions in the standard, there's no exemption from shock. It's just my personal view, but I dont instal without additional protection anymore

 

[leep82]

How have you ensured that only electrically skilled persons will be using the machinery? Someone could be a highly skilled welder and yet have no ability to identify a piece of equipment which has deteriorated electrically.

also, and please dont take this the wrong way, in an earlier reply you cast doubt over whether any of the socket outlets i was installing would need RCD protection.

 

[Lucien Nunes]

Situations where I would exempt a socket outlet from RCD protection are those where the disadvantages of fitting it overshadow the advantages. For example, in my own workshop I have sockets into which strange pieces of equipment, possibly faulty or experimental, are connected for test and evaluation. In this situation unexpected nuisance tripping is likely and might cause undesirable results or prevent the work being completed successfully. A qualified electrical engineer would be supervising, would use appropriate SSoWs, and the sockets are isolated when not in use.

Another situation is where sockets are part of installed systems, e.g. the large ELV DC supplies we install in pipe organs, that use a 13A socket for ease of replacement instead of being hardwired in. They are only accessible to technical maintenance crews often in a permit-to-work areas and will only ever be used for that installed PSU because there's nothing else going on up there. In this application, although the RCD offers little additional safety, a nuisance trip could result in an entire evening's programme being cancelled, as there might be no-one in attendance able to access and reset it in a reasonable time.

Without background knowledge of your site I would say there is merit in RCD protection and no extenuating circumstances that would exempt it. However, there might be specific reasons why the equipment is not compatible, e.g. if the welder is of a type that might generate enough leakage to cause nuisance trips, or if the saw has injection braking where loss of supply could create a greater hazard than RCD protection removes. Those are aspects that needed consideration before installation.

 

[Ian1981]

One of the exceptions of omitting rcd protection for sockets upto 20 amps is a suitably labelled socket for an item of equipment no risk assessment mentioned if choosing this method in bs7671.
One other omission is a documented risk assessment.

If opting for the labelled item of equipment option, why do a risk assessment for it?otherwise you would only have the one option open to you in the first place and not 2 options given in bs7671.