Discuss 2 spurs from a Junction Box....worried? in the Electrical Forum area at ElectriciansForums.net

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I agree, and be7671 doesn't define accessible. this kind of thing is much more common in the design of non domestic installations...

This is why I sometimes come at these debates from a different angle. In industrial design not much about placement is standard enough for regs to cover it. All houses have floorboards and walls where things can be hidden, so it's easy enough to define all such places as needing MF.

Beyond domestic, there is just too much variability though. In a factory process line something could be totally inaccessible without major effort for a variety of obscure reasons, so it really does all hinge on common sense. In the same way bathrooms and kitchens are zoned in respect of them being wet areas. In my world a space not at all zoned could represent similar risks and it's up to me to identify those risks and factor them in to whatever is being installed.

Different worlds I guess... But the risks are in the end, generally comparable.
 
Good idea @Deuce you have persuaded me that an informative appendix defining zones for accessibility would help a lot.
Interestingly part m defines accessibility for their purposes as between 450 and 1200 from ffl, so in New builds most screw connections would be within that range anyway. But I'm not suggesting that is a useful definition for our purposes
 
It's not useful as far as accessibility of connections no - it is purely aimed at ensuring accessibility of user operated switches /sockets etc. Nothing wrong with a jb being on top of a kitchen cupboard for example - it is still accessible.
 
Hum

Inaccessible?
Yes I know Mate just before I hit the post button doooooh Funny how you know you have it wrong, but you still can't stop the finger that's hovering over the send button only to realise what you have done, and hope nobody notices your error. And I haven't any alcohol, yet.
 
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Yes I know Mate just before I hit the post button doooooh Funny how you know you have it wrong, but you still can't stop the finger that's hovering over the send button only to realise what you have done, and hope nobody notices your error. And I haven't any alcohol, yet.
P!SS head lol
 
For those who are worried about overloading terminations by taking two spurs, each to one twin sso from one 30A joint box connected to a ring final cct. Consider a spur from a twin sso on the ring to one twin sso. If these sockets are compared to the two spurs from one joint box you will see the point loading on the rfc is the same in both cases. The load in both cases comes from a single connection to the rfc.
 
For those who are worried about overloading terminations by taking two spurs, each to one twin sso from one 30A joint box connected to a ring final cct. Consider a spur from a twin sso on the ring to one twin sso. If these sockets are compared to the two spurs from one joint box you will see the point loading on the rfc is the same in both cases. The load in both cases comes from a single connection to the rfc.
One twin 13 Amp Socket out let IS ONE SPUR Brian, not two spurs taken from the same point on a RFC.
 
Brian's point is exactly the same as the one I made in post #121 that 11 people liked. The key is that the terminals feeding the two spurs are in a junction box, not the back of another socket outlet. The loading is exactly the same with two spurs from one JB, as with one spur from a socket outlet, as in both cases there are two socket outlets loading a single node in the RFC.

In general the regs don't differentiate between an unfused spur taken from a socket outlet and one taken from a junction box. But here, it's relevant because it eliminates any argument about overloading, regardless of any other factors.
 
Brian's point is exactly the same as the one I made in post #121 that 11 people liked. The key is that the terminals feeding the two spurs are in a junction box, not the back of another socket outlet. The loading is exactly the same with two spurs from one JB, as with one spur from a socket outlet, as in both cases there are two socket outlets loading a single node in the RFC.

In general the regs don't differentiate between an unfused spur taken from a socket outlet and one taken from a junction box. But here, it's relevant because it eliminates any argument about overloading, regardless of any other factors.
Not going there again Lucien, said my piece, was stupid of me to react to Brian's post.
 
*DING* *DING* - Round 2 :D

I think we've done the subject to death and we have concluded that there are two camps... acceptable and not acceptable, and peoples residency in those camps appears to be largely down to interpretation of the regulations and/or their view on whether it's good practice or not.

But one thing I think most of us are agreed on is that under normal circumstances we wouldn't do it this way ourselves.
 
I dont see how putting 2 x JB a foot apart makes any difference electrically provided the JB is sound. The JB is on a leg between 2 points of a ring. The ring cable will carry the same load in each scenario. Theres no danger of overload to the spurs as its 2 x seperate twins off one point of the ring. Wired correctly. Adequate size cable. So why put extra connections in a circuit that doesnt need it??

Completely different to spurring twice off an outlet.
 
I dont see how putting 2 x JB a foot apart makes any difference electrically provided the JB is sound. The JB is on a leg between 2 points of a ring. The ring cable will carry the same load in each scenario. Theres no danger of overload to the spurs as its 2 x seperate twins off one point of the ring. Wired correctly. Adequate size cable. So why put extra connections in a circuit that doesnt need it??

Completely different to spurring twice off an outlet.
Nor do I, but if that was the scenario those who say it does not comply would be satisfied by a short piece of 2.5 between two junction boxes.
 
Nor do I, but if that was the scenario those who say it does not comply would be satisfied by a short piece of 2.5 between two junction boxes.

2 x MF, and an extra piece of cable - yes that would be ideal and then, like the pretty schematic in BS 7671 there would only be 3 cables at each point ....
 
I think it's time to close this thread, it's unlikely any new views will be put forward (as there are essentially only two... it complies and it does not) and well, at 16 pages I think it's run it's course.
 

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