I'm confused about junction box rules

[Risteard]

I try to go above and beyond.

But I'll throw out all my maintenance free jbs on Monday

No need to throw them out. I'm a big fan of J803s and J804s where necessary. I certainly wasn't suggesting that you have to use the old bakelite JBs. I haven't used any of them in years.

 

[pete01]

No need to throw them out. I'm a big fan of J803s and J804s where necessary. I certainly wasn't suggesting that you have to use the old bakelite JBs. I haven't used any of them in years.

I know just messing, I would only use maintenance free so would only advise others to do the same.

 

[JohnW2]

OK. To phrase it differently, which Regulation states that access must be "easy"?

Oh sorry I just use common sense.

Otherwise known as opinion. But we should stick to the facts.

Well yes my opinion is that a jb should be easy enough to get to.

It's certainly my preference also, but it isn't what is required by BS 7671.

Risteard, I think you are missing the point about the real world. Since BS 7671 does not define "accessible", and whether you like it or not, it IS down to opinions (hopefully based on common sense) - and, as we know from countless discussions here and elsewhere, those opinions varying a lot.

Ultimately, those opinions generally are based on 'how easy' access is, since anything is ultimately 'accessible' (even if one has to be 'destructive'). However, even without destruction, opinions vary a lot. Even if there is a screwed 'access panel' in the floorboards, some would regard that as 'inaccessible' particularly if (as would often/usually be the case) one had to lift floor coverings to get at it.

I would suggest that, in formulating opinions, the best test to apply is "would anyone (e.g. an EICR inspector) bother to access this?". The answer to that will depend upon "how easy it is", and I would suggest that in the case of, say, a screwed panel beneath floor coverings, the answer would be that access was not 'easy enough' for anyone to ever bother to achieve that 'access'.

 

[JohnW2]

I'm a big fan of J803s and J804s where necessary.

I quite like them, too, but as I've observed before, there's one thing about them with frustrates me, since it wastes a significant amount of time ...

... I doubt that I am the only person to have discovered that, with all but the smallest of (T+E) cables, I nearly always end up having to completely remove one of the screws from each used cable clamp and hence swing the clamp 'out of the way', since I otherwise find it extremely difficult, if not impossible to get the conductors into the connectors.

For that reason, I now tend to use Wagos in WagoBoxes rather than the Hager/Ashley JBs.

 

[securespark]

I am wondering if the 1/8th rule re spurs is related somehow to the 1/4 rule regarding r1+r2.

 

[JohnW2]

I am wondering if the 1/8th rule re spurs is related somehow to the 1/4 rule regarding r1+r2.

What "1/4 rule" are you referring to?

 

[ebee]

What "1/4 rule" are you referring to?

Might it be the (r1 + r2)/4 = R1 + R2, perhaps ?

and yes I would like to know where the 1/8 idea actually stems from, even as a quick approximation.

 

[Harry Bloomfield]

... I doubt that I am the only person to have discovered that, with all but the smallest of (T+E) cables, I nearly always end up having to completely remove one of the screws from each used cable clamp and hence swing the clamp 'out of the way', since I otherwise find it extremely difficult, if not impossible to get the conductors into the connectors.

Taking all of the screws out first, is always the correct way to tackle them. You then insert all of the bared conductors, into all of the terminals, packing/settling them down, then finally fit and tighten the grub screws. The position of the cables shouldn't move, once loosely inserted, because the box is fixed, and the cables are fixed close to the box, with clips.

 

[JohnW2]

Might it be the (r1 + r2)/4 = R1 + R2, perhaps ?

That's just very elementary arithmetic. If the resistance of L+CPC is "r1 + r2" for the entire ring, then for one of the legs from origin to midpoint, the figure is obviously half of that, and since there are two such legs in parallel between origin and midpoint, the overall L+CPC resistance between origin and midpoint ("R1 + R2") will be half of that half - and half of a half is a quarter

...and yes I would like to know where the 1/8 idea actually stems from, even as a quick approximation.

I'm working on it, but am short on time at the moment. It clearly relies oin assumptions, and is only going to be 'correct' at one point of gthe ring. Watch this space

Kind Regards, John

 

[JohnW2]

Taking all of the screws out first, is always the correct way to tackle them. You then insert all of the bared conductors, into all of the terminals, packing/settling them down, then finally fit and tighten the grub screws.

Yes, that's what one has to do (BTW, they are regular 'screws', rather than grub screws), but it's all a bit tedious, and considerably increases the amount of time it takes to do the job.

It may not be quite as 'solid' a method of cable restraint (although I'm sure is perfectly adequate), but the 'push-in restraint' of a WagoBox is dramatically simpler/quicker!

 

[EFLImpudence]

and yes I would like to know where the 1/8 idea actually stems from, even as a quick approximation.

It's a mistake.

The same as where on page 20 in 2.2.3.1 it states that consumers' tails must be 25mm².

 

[blup]

I nearly always end up having to completely remove one of the screws from each used cable

First world problems? Ashley are much easier to work with imo.

I would suggest that, in formulating opinions, the best test to apply is "would anyone (e.g. an EICR inspector) bother to access this?

Arguably an unhelpful comparison given so many EICRs involve only inspection of selected circuits. Rumour has it that some sparkies regard the actual house as inaccessible so conduct a drive by assessment.

 

[securespark]

 

[SUNRAY]

First world problems? Ashley are much easier to work with imo.

Arguably an unhelpful comparison given so many EICRs involve only inspection of selected circuits. Rumour has it that some sparkies regard the actual house as inaccessible so conduct a drive by assessment.

Certainly seems to be the case in a number of rental propeties I've attended to make the 'repairs' where the tenant states there has been no inspection or things like no immersion heater or metal accessories as mentioned on EICR.

On one there was no E7 system or NSHs to require RCD protection

 

[JohnW2]

It's a mistake.

It's not actually a 'mistake', but it's a very unhelpful 'rule of thumb' - see what I will be posting shortly!