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Author Topic: NTE5 spark gap question  (Read 1888 times)

Weaver

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NTE5 spark gap question
« on: January 14, 2019, 07:43:07 PM »

According to the wikipedia article on BT phone sockets, I might or might not have spark gap lightning protection in my NTE 5a’s. This means in the back part surely?

It says ‘until recently’ but that doesn’t tell me much. Doesn’t anyone know?

So were engineers constantly replacing them when they blew? Assuming (hoping) that they were fail-safe so as to alert the customer after failure as opposed to fail-carry-on-unprotected.

The article says that was discontinued because of affecting VDSL2?

Does that mean NTE5a’s were swapped out routinely? I find that a bit hard to believe because of the scale of the swap outs for FTTC.

My question: is there any chance of getting spark gap type of NTE5a put in by Openreach, as I really need the lightning protection? (Not for free obviously.)
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burakkucat

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Re: NTE5 spark gap question
« Reply #1 on: January 14, 2019, 08:29:13 PM »

We* have discussed this topic previously and with a careful search earlier posts should be found.

I have a vague recollection of connecting a spare, early 1980s vintage, NTE5A to my Ohmmeter 18C. At 95V the over-voltage device was not triggered. At 500V it operated and displayed a delicate violet glow. Ah, here is a post that I made on the subject.

If the NTE5A has IDCs, rather than screw terminals, for the network connection (the Openreach side) then there is a strong possibility that there is no over-voltage device present.

For adequate protection, there needs to be a good, low impedance, connection to earth and when the device strikes it should clamp both wires of the pair together and directly to earth.

Ideally you would like to have the same protection for each of your four circuits (at the point where they enter Torr Gorm) as that which is present for every circuit at the exchange end. How often is an exchange zapped by a lightening discharge? Probably never. (Perhaps Liquorice or 4C could let us know their experiences of such events?)

I'm sure if you could find the right person, to which your request should be directed, Openreach would be prepared to arrange the installation. Obviously money would have to be exchanged.
 


* The forum community.
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licquorice

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Re: NTE5 spark gap question
« Reply #2 on: January 14, 2019, 10:13:30 PM »

Have to say I've never had any experience of an exchange strike or any damage due to lightning, but I have certainly seen the after effects of an overhead line strike at a customer's premises, not pretty!!
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Weaver

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Re: NTE5 spark gap question
« Reply #3 on: January 15, 2019, 08:12:50 AM »

Many thanks to the Kuro Neko for digging up that thread for me - I’m hopeless at searching. (Drug fog.) There’s some brilliant material there covering things very thoroughly.

So since I have IDCs that means no spark gap? There may be one 2003 NTE5, two 2010, 2011 or thereabouts and finally an NTE5c summer 2018.
« Last Edit: January 15, 2019, 08:18:34 AM by Weaver »
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4candles

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Re: NTE5 spark gap question
« Reply #4 on: January 15, 2019, 03:49:40 PM »

It was all a looong time ago....   :oldman: but the only damage I can recall was one particular TXE2 exchange where it was quite regular to change a dozen or more welded reeds after a storm.IIRC there was something about the local topography which 'funnelled' storms into the area.
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burakkucat

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Re: NTE5 spark gap question
« Reply #5 on: January 15, 2019, 04:23:51 PM »

So since I have IDCs that means no spark gap? There may be one 2003 NTE5, two 2010, 2011 or thereabouts and finally an NTE5c summer 2018.

The NTE5C most definitely does not have an over-voltage device. The NTE5As from 2010/1 would have none. The oldest, from 2003, probably does not . . . unless it was very old stock from the 1980s that was found in the back of Hamish's van.
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Weaver

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Re: NTE5 spark gap question
« Reply #6 on: January 17, 2019, 01:51:42 AM »

Many thanks for clarifying that.
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JGO

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Re: NTE5 spark gap question
« Reply #7 on: January 17, 2019, 08:36:43 AM »

The demise of protection may be connected with the non- availability of Metrosil the non-linear material from which inter-alia, "Telephone Line Protector Blocks " used to be made..
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tubaman

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Re: NTE5 spark gap question
« Reply #8 on: January 20, 2019, 10:19:02 AM »

A quick rummage in my 'useful telephone parts' box revealed this.
I pulled out the spark gap, which is clearly designed to be replaceable, and it appears to show a 1989 manufacturing date.
 :)
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Weaver

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Re: NTE5 spark gap question
« Reply #9 on: January 21, 2019, 02:59:21 AM »

Is that the spark gap there?
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tubaman

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Re: NTE5 spark gap question
« Reply #10 on: January 21, 2019, 08:14:37 AM »

The spark gap is the part just to the left of the screw terminals.
 :)
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BT FTTC 80/20 Huawei Cab - Zyxel VMG8924-B10A
 

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