16amp socket advice

[Oatcake]

Hi there,

This is my first post here so go easy....

I’m on the verge of buying a new table saw and a few of the ones I have shortlisted require a 16 amp socket. Before I arrange installation is there anything I should be considering when getting the job done?... obviously getting it done properly is a given but is it best to have multiple sockets installed or just one, should it be switched...I could be overthinking it maybe.

Thanks,

Ade.

 

[Ollie78]

Mine don`t have a switch on the sockets themselves.
Remember its not just the socket that is important but the type of MCB its attached to, it should be a type C at 16 amps.

Ollie

 

[Lons]

Mine is like this one as I prefer it switched off when not in use so no possibility of accidental starting also I'm happier that the current stops at the socket rather than the saw switch panel. Probably OTT but makes me feel better.

 

[Spectric]

Before you go down this route make sure that the table saw actually requires one. Some state that are fitted with a 16 amp plug but when you look at the specs they don't really need one. My table saw is a 315mm Schepach with a 2200 watt motor and it has a 13 amp plug and has never given any issues. 2.2Kw with a Pf of 1 requires 9.6 amps, but you will have a larger initial startup current.

 

[Oatcake]

Ollie, Lons, Roy - Thanks for the replies.

I like the switch idea, definitely will go with that. Good point Roy but I’ll play safe and go with the specs of the equipment. Will mean I don’t have to hold my breath every time I turn the saw on.

 

[julianf]

16a connectors are unfused, so you will need the breaker as well as the actual plug.

I guess you could rely on the rings breaker, but i prefer to fit one to by the socket, as the ring is more likely on a 32a.

 

[OxonTurner]

Just had mine done by contractor for piece of mind, although my workshop was only built in 2009 it wasn't feed with a 10mm earth, just standard twisted pair with 6mm earth. He couldn't sign off on paperwork without this so got him to fit correct earth. So one thing to think about.

 

[clogs]

just an add on.....
just by the door is my mains feed isolator (3phase).....it has a big hand cranked lever.....
as I walk out the shop it get turned off....
that means everything is dead.....
I do have an led 4' strip left on 24/7 but that has a totaly seperate feed....
Plus the shop has it's own earthing rod as well as connected to the mains earth.....

 

[Robbo60]

As above, important breaker is type C. My workshop is fed by a type B and it trips when I switch the table saw on. Need to get it changed but beyond my skill set

 

[pe2dave]

1. Suggest no to multiple sockets, if on the same ring? Current limit issue.
2. Suggest (if practical) the socket is mounted high for ease of access.

Make sure the lecky can leave a compliance cert before you pay him.
The next house owner can ask for it.
HTH

 

[Spectric]

16a connectors are unfused, so you will need the breaker as well as the actual plug.

I guess you could rely on the rings breaker, but i prefer to fit one to by the socket, as the ring is more likely on a 32a.

Hi

You cannot connect a 16 amp socket to a circuit that is protected by any 32 amp protective device whether that is an old fashioned ring or a radial. Each 16 amp socket needs a dedicated protective device in the board. This is also the same issue when fitting modern ovens that are european as they also require dedicated 16 amp supplys. The only machine I have that required a 16 amp supply was my PT107 planer thicknesser but that was not due to running current only initial startup current which sometimes took out the 13amp fuse in the plug which could be annoying. As has been previously mentioned in threads you cannot just fit a type C in place of a type B, you must know the circuit impedances but this is more of an issue when twin & earth cable has been used for the instalation, the CPC is only 1.5mm and is why industrial installations use singles.

 

[julianf]

Are you saying that you cant have a ring on a 32a breaker, and then a 16a breaker and socket off that ring?

Can you let me know why? Im thinking that with a standard domestic double socket and a couple of heavy draws plugged in, youre well above 16a from a single connection to the ring, so, with simple laymans logic, im at a loss to know why its not acceptable to draw 16a through a breaker and a socket?

 

[julianf]

Possibly we are in confusion here -

My statement was that you could NOT install a 16a socket on a ring protected by a 32a breaker, without its own breaker.
I implied that (maybe) you could if the ring was protected by a 16a breaker, but that i would prefer to fit individual breakers.

Are you saying that it would be unacceptable to install a 16a socket onto a ring that was protected by a 16a breaker at source? I can see this might not be the best idea, however, i cant see what the danger point might be?

Note, I'm not an electrician, so will never pretend to know the regulations for all of this, but still can not understand the danger point of the above?

 

[porker]

Because it won't meet the regs for one. You can only take a 13A spur from a ring. In theory what you state would probably work in 2.5mm cable but it is not good practice.

 

[pe2dave]

KISS principle?
Installed by an electrician, not on the ring, had own 13A cable (normal ring main cable) direct to 16A socket. Trip on fusebox,
I don't think there was a fuse on the socket.

 

[Spectric]

Are you saying that you cant have a ring on a 32a breaker, and then a 16a breaker and socket off that ring?

Domestic is always a pain in the rear, if people used industrial standards in their workshops it would be much easier. You can have a ring on a 32 amp breaker, a 4mm radial on a 32 amp breaker or a 2.5mm radial on a 20amp breaker. Now if you connect a 16amp socket to a ring protected by a 32amp protective device then the only protection for anything connected to this socket is that 32amp device and it is more than possible that the cabling will not handle the prospective fault currents which for a type B32 are 5 times 32 or 160 amps. The issue with any domestic 13amp circuit is that the total load is unknown, it all depends what people connect to it but we do know the maximum load at any point will be 13amps . The regs state that 16 amp outlets should be on circuits no greater than 20 amps. Now in a domestic situation, in your workshop if you had a 20 amp radial with some 13amp sockets then there is no reason why you should not also connect a 16 amp socket bearing in mind the total load but this is not regarded as good practice for the installation of domestic appliances such as ovens. I would always recommend taking a more industrial approach to wiring in a workshop enviroment, use singles and not T&E and run 2.5mm CPC's, and now a grey bit because in true industrial enviroments each machine will be hardwired/plugged into an isolator that has its own set of fuses in a local distribution board and all the machinery can run at the same time. Ok there are exceptions where the total load would exceed the incomming supply, recalling a job where the company had some big 100Kw motors and we had to provide interlocks to prevent excess loads but in your one man band workshop you will not run multiple machines at the same time so having say four 16 amp sockets on a 2.5mm radial from the board is ok because the wiring is protected, if you did run four 2.2kw loads simultanously the protective device would trip, although not within 0.4 seconds. Now the issue, it is ok to have multiple 13 amps sockets on a type B protective device but not a type C, hence why some modern refrigeration appliances have a dedicated connection fed by it's own type C RCBO. It should always be remembered that the only way to ensure everything is correct and will function as per your design is through testing, you need the values to confirm what you think is actually correct.

 

[Chippymint]

Very informative Roy and I'm pleased you wrote this as some if the articles I read are scary. Many seem to rely on the fact theve not had an issue then that's all fine then. Well done.

 

[Felix]

It's really scary what some people tell other people what's right and wrong with regards to electrical installation/modification. To the interested parties looking at this thread if you follow @Spectric's advice you will not go far wrong. I would add that as a rule of thumb a 'commando' type socket is more for portable equipment - something that is likely to be moved or a rotary isolator if the equipment is static (usually heavy equipment that is unlikely to be moved). Having said that, either method is fine - local isolation is the key here.

 

[bussy]

Spectric, My thoughts the same as yours, my new workshop (if i ever get the planning sorted) will have two consumer units one to feed 32A ring main, lights, alarm etc and a separate board to supply large machines, each machine on its own rcbo (type c) terminated with an isolated commando socket. wiring will be singles in steel trunking.

 

[Spectric]

Firstly I would not bother using ring mains, old hat these days so instead run radials. Also use a single board rather than two, simplifies the cable runs from the level 1 board. The design has to start at the point of supply which I assume is a 100 amp domestic single phase supply or is it an industrial supply?