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John Rumm John Rumm is offline
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Default Mad electrical question

On 22/03/2019 15:17, wrote:
On Friday, 22 March 2019 11:02:19 UTC, John Rumm wrote:
On 22/03/2019 01:26, tabbypurr wrote:
On Thursday, 21 March 2019 16:41:09 UTC, dennis@home wrote:
On 21/03/2019 16:12, tabbypurr wrote:
On Thursday, 21 March 2019 12:53:00 UTC, dennis@home wrote:
On 20/03/2019 19:39, ARW wrote:
On 20/03/2019 18:11, Scott wrote:

I discovered a problem with a join in a ring main and decided to
replace the faulty connector with a terminal block.Â* I wondered if
this needs to be rated at 30A to correspond with the fuse (RCBO) or if
15A would be okay on the basis that it is a ring and some of the
current will go each way round.

On the Brunel principle I am fitting 30A but I am curious to know.


https://www.youtube.com/watch?v=2uYD8e7idnY


The video shows that the connectors will carry the current when new.
But what happens after they have had a few thermal cycles?
I would think the wire nut and the choc block will fail first.

Choc block & crimp are gas-tight, so should last.
Wago might be gas tight if the wire is never moved, it certainly won't be if any movement occurs.
Wirenuts aren't gas tight. US electrical fires are a testament to that.


NT


choc block are not gas tight.

yes they are. You're free to go & learn something.


That does rather depend on if there was adequate screw pressure created
when the termination was made.


obviously


Its not always easy to judge though since it depends on the area of the
screw "point". Some older fittings had quite large diameter screws that
needed lots more pressure to bite into the copper and form a gas tight
seal.

Also on terminations that cycle through a
larger temperature range, its not uncommon for terminal pressure to
loosen with time.


occasional loosening is their one weakness. I trust them far more than wirenuts or sprung pushins though.


Don't think I have ever met a real wirenut in fixed wiring applications...


--
Cheers,

John.

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