Ashley J803 and J804 Junction Boxes

[JohnW2]

There is a separate discussion going on as to whether Ashley’s J803 and J804 ‘maintenance-free’ junction boxes are suitable for use in inaccessible locations. However, that discussion aside, there is one point about these products which has aroused my curiosity ....

They look to be well-designed and well-engineered products; the cable clamps, pretty unique amongst JBs, are particularly welcome. The J803 and J804 are almost identical, both containing groups of four interconnected push-button-operated spring terminals, each with a specified conductor capacity of 0.5mm² – 4mm². Both say that each of the (four) cable clamps can take up to 2 x 2.5mm² T&E cables or 1 x 4mm² T&E cable. As far as I can make out, there are only two differences between the J803 and J804:

• 1...In the J803, one group of 4 terminals is absent (those labeled as ‘loop’/’L2’ in the J804).
  2...The covers are different, but only in that the J803 has ‘32A’ on it and the J804 has ‘20A’ on it.

My curious mind is just pondering why addition of the fourth group of (seemingly identical) terminals in the J804 brings about a reduction in current rating from 32A to 20A. Any ideas?

Kind Regards, John.

 

[Paul_C]

Although the terminals are the same, maybe they're just using the different ratings to match up with the common 3-way 32A and 4-way 20A screw-terminal junction boxes.

 

[holmslaw]

..

 

[JohnW2]

Although the terminals are the same, maybe they're just using the different ratings to match up with the common 3-way 32A and 4-way 20A screw-terminal junction boxes.

That's all I can think of, although it seems a little silly (from their point of view). If, as seems very probable, the 4-way product is just as capable of carrying 32A as is the 3-way one, why 'undersell' the product in its description/'rating'?

... and the terminals certainly do seem identical - not only in terms of external appearance of the terminal blocks, but I've also taken them apart, and the innards seem identical as well.

Kind Regards, John.

 

[JohnW2]

The pull-out strength of these terminals is certainly quite impressive, at least initially:

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I had to remove the connector block and test it alone,since forces of 10-15kg pull the block out of the clips in the housing. However, as you can see (sorry about the reflection on dial), it only just starts slipping (although still held firmly) at around 45lb/20kg, and actually does not come out until 30+ kg.

Kind Regards, John

 

[333rocky333]

With similar push in terminals, I thought the things were designed to let the wires pull out.
Im sure i read the tension is only to ensure a decent connection rather than the wiring puling out.
I know many lighting units have stamped on them pull wire to remove, yet in reality its not that easy.

 

[JohnW2]

With similar push in terminals, I thought the things were designed to let the wires pull out. Im sure i read the tension is only to ensure a decent connection rather than the wiring puling out. I know many lighting units have stamped on them pull wire to remove, yet in reality its not that easy.

They're not really 'push-in'/'pull-out' terminals, in the sense of pushing in/pulling out against resistance. Instead, one pushes down (hard!) on the 'button at the top' to remove the spring pressure - hence can push in (or pull out) the conductor with no resistance at all.

The sort of resistance to pull-out that I described obviously would not be achieved with friction due to spring tension alone. Instead, the leaf of the spring, with a 'sharp' end, sits at a very acute angle to the conductor, and hence 'bites in'. If one attemps to pull out the conductor without depressing the button (as per my bench test), if one does get it out there will probably be damage to conductor and/or the terminal spring:

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In passing, if one wants to 'enjoy' the benefits of the cable clamps but doesn't want to use these 'maintenance-free' terminals, bits of connector strip fit nicely into these enclosures:

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Kind Regards, John.

 

[ban-all-sheds]

Ring Ashley.

And if she's not in ask for Mary-Kate.

 

[sparkiemike]

The pull-out strength of these terminals is certainly quite impressive, at least initially:

What purpose would this test serve and what is the purpose of this post? Surely you would have noticed the strain relief clamps, if used properly the terminals would not be exposed to such stresses.

 

[JohnW2]

What purpose would this test serve and what is the purpose of this post? Surely you would have noticed the strain relief clamps, if used properly the terminals would not be exposed to such stresses.

Yes, I noticed ...

the cable clamps, pretty unique amongst JBs, are particularly welcome.

As you say, in practice (provided the clamps are used), there is going to be no significant pull-out force. The purpose was mainly one of curiosity, given that pull-out resistance is one of the things that Ashley boast about when arguing that the product is "compliant with the intent of" 526.3 of the regs, but it also provided some sort of handle on the integrity of the contact between conductor and connector (although I didn't mention it, as you will imagine, the contact resistance was too low for me to measure and nor was there any measurable temperature rise at rated current).

Kind Regards, John.