Double or two singles what is it?

[ericmark]

I wanted two sockets one for heating and one for cooling to build in to a thermostat to control my fridge and heat pad for brewing beer.

I wanted at first a twin socket box and two single sockets but didn't seem to be available for surface mount. Then I found LAP grid sockets and realised I could fit two into a 4 module wide plate which would fit a double socket box.

This was ideal as one can be wired for heating and other for cooling and I realised these sockets would also be ideal for extending a ring from a double socket.

But then I started to wonder with a unfused spur we are allowed either a single of double socket. But we are not allowed two single sockets.

I have considered this rule is to stop being able to open a single socket and think it's on a ring because of having two cables.

So question with an unfused spur from a ring are two sockets fitted to same face plate counted as a double socket or two single sockets? If counted as a double what about two singles in a twin socket box?

Next question where you want to take a second spur from a double socket on a ring would using one of these grid plates with two sockets allow it to be done? I see two reasons for only one spur from a socket.
1) Limits cables to three.
2) Limits draw on one point of the ring.

So what are these grid sockets classed as. At the moment I have no need to fit a second spur or to extend a ring but the time to decide what is allowed is before the need arises so one has the answer ready.

 

[deadshort]

Hi, i would spur from the ring >FCU>into your thermostat > 2x 1g sockets in a dual 1g surface box.

The 1g grid sockets could not be installed as a spur from the ring as a double because they are two separate accessories and two single sockets cannot be fitted from an unfused spur from a ring.

You could use a grid fcu to supply two 1g grid sockets that would be a tidy solution for your hot and cold sockets!

Regards,

DS

 

[bernardgreen]

You need to search for dual patress and not twin

http://www.edwardes.co.uk/en/produc...ource=google&utm_campaign=google_shopping&p=1

was the first using google and not the cheapest.

Using a dual box and two singles is a good way to insert extra sockets into a ring. Not a good as re-routing the existing ring but for retro fit it is OK provided the two sides are totally separate electrically.

 

[JohnW2]

I wanted two sockets one for heating and one for cooling to build in to a thermostat to control my fridge and heat pad for brewing beer. I wanted at first a twin socket box and two single sockets but didn't seem to be available for surface mount.

For one of many findable by simple Googling (click here) .

Then I found LAP grid sockets and realised I could fit two into a 4 module wide plate which would fit a double socket box. ... This was ideal as one can be wired for heating and other for cooling and I realised these sockets would also be ideal for extending a ring from a double socket. ... But then I started to wonder with a unfused spur we are allowed either a single of double socket. But we are not allowed two single sockets. ... I have considered this rule is to stop being able to open a single socket and think it's on a ring because of having two cables.

That could be the reason, it could have just been an 'oversight' (or lack of clear thinking!) or it may be the result of believing (as most people do) that the maximum potential load presented by two single sockets is greater than that presented by a double socket.

So question with an unfused spur from a ring are two sockets fitted to same face plate counted as a double socket or two single sockets? If counted as a double what about two singles in a twin socket box?

Particularly given your intended application, this is obviously more of a question about strict adherence to regs than to electrical common sense. However, as for the former, as deadshort has pointed out, in strict terms the regs would probably regard two socket modules as two accessories, hence not allowed on an unfused spur.

However, as deadshort has also said, why not simply used a fused spur (13A would presumably be adequate for your purpose) - after which you could do whatever you wanted, sockets-wise?

Next question where you want to take a second spur from a double socket on a ring would using one of these grid plates with two sockets allow it to be done? I see two reasons for only one spur from a socket. 1) Limits cables to three. 2) Limits draw on one point of the ring. ... So what are these grid sockets classed as. At the moment I have no need to fit a second spur or to extend a ring but the time to decide what is allowed is before the need arises so one has the answer ready.

To start with, AFAIAA, there is no regulation which explicitly prevents two spurs having their origin at the same point on a ring, the only real requirement being that the designer must satisfied that it is unlikely that this will result in any of the ring cable being 'overloaded' for 'long periods of time'. There may, of course, be a problem of putting more than three conductors into a socket terminal, either physically or because of the MIs.

Kind Regards, John

 

[EFLImpudence]

There may, of course, be a problem of putting more than three conductors into a socket terminal, either physically or because of the MIs.

I don't consider a statement that the terminal takes 2x6, 3x4, or 3x2.5 or whatever to be an instruction but merely information as it does not relate to the current.
That the terminal can take 2x6 and 3x4 clearly means it can take 4x2.5.


Anyway, pretending it IS an instruction, what about terminating the four conductors in a connector with another from the connector to the socket terminal?

 

[JohnW2]

There may, of course, be a problem of putting more than three conductors into a socket terminal, either physically or because of the MIs.

I don't consider a statement that the terminal takes 2x6, 3x4, or 3x2.5 or whatever to be an instruction but merely information as it does not relate to the current. That the terminal can take 2x6 and 3x4 clearly means it can take 4x2.5.

I agree that it can be difficult at times to decide whether something is 'an instruction' or 'information'. Hopefully, come next year, we will be able to apply common sense, even if it may be 'an instruction'. I agree that most sockets will happily take 4 x 2.5mm² - I've certainly done it on a good few occasions!

Anyway, pretending it IS an instruction, what about terminating the four conductors in a connector with another from the connector to the socket terminal?

Indeed. That would obviously technically make the socket an 'unfused spur' from the ring - but since it's just one socket, that's not a problem. As I said before, the designer would, of course, still have to satisfy him/herself that the origination of two (or, with the arrangement you're suggesting, three) spurs from the same point on the ring is not likely to result in the CCC of the cable being exceeded for 'long periods of time'.

Kind Regards, John

 

[deadshort]

I am interested to hear the views the electrcians on the forum if they would agree with connecting 4x 2.5mm cables into a socket. I would have had my ar….e booted if i had tried it during my apprenticeship !

Regards,


DS[/u]

 

[EFLImpudence]

I am interested to hear the views the electrcians on the forum if they would agree with connecting 4x 2.5mm cables into a socket. I would have had my ar….e booted if i had tried it during my apprenticeship !

For a good reason or because of lack of knowledge and common sense on the booter's part?

 

[deadshort]

I would imagine something to do with standards of workmanship and insurance.

Kind regards,

DS

 

[EFLImpudence]

I would imagine something to do with standards of workmanship and insurance.

The reasons for which are what?

Independent thought not allowed?

 

[deadshort]

Which are what ? !!!!! t'wit ta woo ? is it a game ?

Regards,

DS