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Topic Title: Quality of 2 pole isolators
Topic Summary: Fitted by DNO's etc..
Created On: 25 February 2019 08:27 pm
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 25 February 2019 08:27 pm
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mikejumper

Posts: 2810
Joined: 14 December 2006

Has anyone else experienced problems with the outgoing terminals of DNO fitted isolators. There were 4 tiny Allen head screws (two for Live, two for Neutral). I needed to remove tails from these terminals today and found one of the 4 heads had been rounded off by whoever fitted it. The make was Proteus, I thought DNO's, meter fitters etc..would have access to better quality stuff than that.
 25 February 2019 08:30 pm
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Zoomup

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Joined: 20 February 2014

China's best.

Z.
 25 February 2019 08:31 pm
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mikejumper

Posts: 2810
Joined: 14 December 2006

Originally posted by: Zoomup
China's best.
Z.

If that's their best, how bad must the bad stuff be?
 25 February 2019 08:32 pm
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Zoomup

Posts: 6117
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Isn't Proteus stuff out of the C.E.F. stable?

Z.
 25 February 2019 08:35 pm
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gel

Posts: 296
Joined: 13 February 2005

Yes CEF associate company, as is TAMLITE.

-------------------------
Gel__Big Brother is here
 25 February 2019 09:14 pm
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alancapon

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Originally posted by: mikejumper
. . . The make was Proteus, I thought DNO's, meter fitters etc..would have access to better quality stuff than that.

Actually, the Proteus isolators used by DNOs are one of the best on the market at the moment. As long as the correct allen key is used (DNOs usually use an insulated "T-bar" key of the correct size), there should not be a problem and we have found them very reliable in service. They are also one of the few isolators that use two screws per termination.

Regards,

Alan.
 25 February 2019 09:53 pm
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mikejumper

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I'm surprised Alan.

Does the T bar have a torque setting facility or is reliant on the judgement of the installer?

And why the tiny Allen heads when you are having to tighten onto such large cables? Imagine the trouble we'd have if the incoming terminals in a CU's main switch were like that.
 25 February 2019 10:11 pm
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alancapon

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The T bars we have, are made with a relatively short top. This makes it very difficult to overtighten a screw. The Allen key end is also cut flat rather than rounded. This means that it is either engaged with the screw or not.

We do also have insulated torque drivers, which are becoming the tool of choice.

Regards,

Alan.
 25 February 2019 10:40 pm
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chrispearson

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Originally posted by: alancapon

The T bars we have, are made with a relatively short top. This makes it very difficult to overtighten a screw. The Allen key end is also cut flat rather than rounded. This means that it is either engaged with the screw or not.

We do also have insulated torque drivers, which are becoming the tool of choice.


When my new meter was installed, the fitter started with an insulated T-bar which clicked after initial tightening. I asked whether it was a torque driver, but he said no, it was just worn. Final tightening was by a newer, and less worn one.

You may be assured that my end of the tails was properly torqued.
 25 February 2019 11:16 pm
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mapj1

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for unskilled use, it may be better with a jumbo version of a lever action wago, like they make for DIN rail example
They do make some that are large enough and will take a human finger into the terminal (and do it some injury if closed) . However, such silliness is not recommended.

-------------------------
regards Mike
 26 February 2019 03:38 am
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dustydazzler

Posts: 3068
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Originally posted by: mikejumper

Has anyone else experienced problems with the outgoing terminals of DNO fitted isolators. There were 4 tiny Allen head screws (two for Live, two for Neutral). I needed to remove tails from these terminals today and found one of the 4 heads had been rounded off by whoever fitted it. The make was Proteus, I thought DNO's, meter fitters etc..would have access to better quality stuff than that.


You can pick up a proteus isolator for about 8 quid on eBay.
At that price I wouldn't be expecting much quality
 26 February 2019 04:21 am
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Jaymack

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Originally posted by: mikejumper
Has anyone else experienced problems with the outgoing terminals of DNO fitted isolators. There were 4 tiny Allen head screws (two for Live, two for Neutral). I needed to remove tails from these terminals today and found one of the 4 heads had been rounded off by whoever fitted it. The make was Proteus, I thought DNO's, meter fitters etc..would have access to better quality stuff than that.

Don't blame the equipment. blame the workman and his lack of correct tools. In the 50's, Japan had the reputation for poor quality, Most Chinese electrical switchgear products are OK.

Regards
 26 February 2019 05:41 am
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ebee

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Can`t say I`ve ever been impressed by Proteus anything up until now that is. I never shop at City either.

First thought is hex key not my first choice but hey ho if correct size (of grubscrew that is to give enough force) might be ok though. Two screws per termination gets a big thumbs up from me especially if the business end has a domed profile. So they might well be pretty good after all.

Call me old fashioned but anyone who needs a torque ratchet just aint cutting the mustard, practice, practice and practice rather than W F F O.

edited ref grubscrew

-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik

Edited: 26 February 2019 at 10:35 am by ebee
 26 February 2019 09:23 am
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Zoomup

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A review of the beast. (If it's the same one).

http://www.cef.co.uk/catalogue...meter-isolator-switch

Z.
 26 February 2019 10:54 am
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mikejumper

Posts: 2810
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Originally posted by: alancapon
The T bars we have, are made with a relatively short top. This makes it very difficult to overtighten a screw. The Allen key end is also cut flat rather than rounded. This means that it is either engaged with the screw or not.

That's getting on towards a specialised tool.

As these terminals are available for electricians to connect to, that arrangement is not conducive to secure and safe termination of tails.

If they have to be Allen screws then they need to be at least 3 times larger, or better still, standard screw terminals that you can get a decent hold on with a screwdriver.
 26 February 2019 11:08 am
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dustydazzler

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are the hex key or square key ?
 26 February 2019 11:33 am
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AJJewsbury

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That's getting on towards a specialised tool.

I wouldn't have thought of a set of allen keys as specialist these days - you can hardly assemble an Ikea flat pack without needing one - and they're already common on some electrical accessories (a certain well known brand of earthing nuts for example). Traditional screw heads are not ideal where you want to transfer a decent amount of torque - because of their tendency to cam out, especially if either the tool or screwhead is a tiny bit worn - a deeper recess with parallel sides works a lot better in that respect - hence the torx head on joist screws and the like and the hex/Allen recess on most DNO cutout terminals. In some areas there's even a fashion for a square recess. Yes, there's always the risk of someone knackering things by forcing the wrong or badly worn tool (like in the old days when phillips screws were new and people used to try to use a small flat screwdriver to turn them) but until we find a way of successfully legislating against idiocy, then we'll have to live with that whatever the recess. Just as long as nothing else gets those horrid +- head that seem so popular on MCBs etc at the moment - they just seem to combine the worst features of both systems without the benefits of either.

- Andy.
 26 February 2019 12:19 pm
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Zoomup

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Not quite so bad as the piff poor plastic connection boxes on many new cookers and overs that come with no flex. Shoddy plastic that distorts when you try to tighten the Torx screws. Then the cheap flimsy plastic cover fights back when you try to fix it back on afterwards.

Z.
 26 February 2019 12:53 pm
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mikejumper

Posts: 2810
Joined: 14 December 2006

Originally posted by: AJJewsbury

That's getting on towards a specialised tool.

I wouldn't have thought of a set of allen keys as specialist these days -

It was Alan's comment about the key being cut flat rather than rounded that suggested to me an element of custom design in the tools they use.

Allen keys are fine as long as they are of a suitable size for their purpose. In this case, in my view, they are just far too small.
 26 February 2019 12:54 pm
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mikejumper

Posts: 2810
Joined: 14 December 2006

Originally posted by: Zoomup
Not quite so bad as the piff poor plastic connection boxes on many new cookers and overs that come with no flex. Shoddy plastic that distorts when you try to tighten the Torx screws. Then the cheap flimsy plastic cover fights back when you try to fix it back on afterwards.
Z.

Don't start me on cooker terminals as well Z.
IET » Wiring and the regulations » Quality of 2 pole isolators

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