bonjovi

just read all your posts and just wanted to add a little myself regarding the time it takes to make off and terminate the 240mm cable

with it being a large armoured its depends mostly on what space you have inside the panel or isolater.this factor depends on how long it takes to complete the instalation a small space takes alot longer the pic above would be easy as their is plenty and generally would be done with someone to help .

Docara

Hi Joe

Sorry for the delay in replying - work commitments

4 hours to make off a 240mm cable possibly longer - it does depend on how many cores the cable has and where the actual termination point are in relation to the cable entry.

With reference to you picture "an example of what we are looking for" - I sincerely hope to GOD it is not what you are looking for!!!! That crap is NOT to British standards OR to British workmanship (of a proper spark)

1. Wrong conductor colours

2. No non-conducting barrier between phase connections (these are standard on British Standard fixings to prevent flash over

3. No barrier OVER the connectors to prevent accidental touching

4. Those banjos (rings with a hole in them) need to be connected to earth - at least to the enclosure that would continue the earth potential to the armour

5. Generally bad workmanship and very messy

6. No way to identify which earth is associated to which cable which we use carry out the initial dead tests to verify Polarity, Phase rotation, R1+R2, Insulation Resistance test before we then continue on to the live tests (Prospective Fault Current, Prospective Short Circuit Current, Earth Fault Loop Impedance test and the five RCD (GFI) tests

I will try and get a picture over the next couple of days of how a typical British SWA installation should look like. The problem I have is that I am working on a petrochemical site that does not allow ANY type of consumer electronics on site unless intrinsically safe.

MDskunk the 'hairs' you refer to are the individual armour cores the thickness of which varies depending on cable size, if you make off the gland properly ie tighten it !!!!! When you 'wiggle' the cable as you say the enclosure would bend and break and the compression fitting to the armoured cores would still not budge!!

Frenchelectrician only seems to have an overview of our system his advice is close enough to be believed or relied on but not right - be warned. Sorry Frenchelectrician it is not meant to be personal eg you say the cable needs to be 'Meggered' - Megger is a brand name of a testing equipment manufacturer that used to be Avo. You are refering to carrying out an Insulation Resistance test - generally passing 1000v in turn between cores to verify the cables integrity. It forms a small part of a sequence of test before we issue a electrical certificate.

Regards
Docara

MDShunk

You'd be interested to know that in the US, when a person talks about "Meggering" something, they're talking about doing an insulation resistance test, the same way when I talk about Xeroxing something, I'm talking about making a photocopy.

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Trimix-leccy

What he said!

In 35 years I have never called it an 'insulation resistance measurement test.'....always called it a megger test.

Same as Hoovering the carpet {i Have a Dyson, but I do not 'Dyson' the carpet} it's just a generic name that has come into common use


Sorry

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TRIMIX...Deep down you know you want it! Trimix-leccy; pulling the envelope---not pushing it

Docara

Hi MDshunk

Interesting I didn't know that.

I have to be honest I was doing you American sparks a disservice - for some reason I was under the impression you didn't carry out the same number or depth of tests that we have to.

What tests to you guys have to carry out before you 'sign off' an installation?
Do you also have to measure the times that RCDs (GFI) take to trip

Regards
Matt

MDShunk

I think you already know the answer to that, and this is part of a setup whereby you type in a manifesto on how bad we do things here. I'll save you the time and just say that we just install the stuff, without testing, and hope for the best.

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Docara

NO WAY!!!!!!

You Serious???

When you walk away from your installations how do you know if it is safe - that some other trade hasn't put a nail through a cable etc etc surely you must verify your breakers will trip in your regulations time frame under simulated fault conditions?

For example an RCD Test - If an RCD is rated at 30mA we have to verify that at 50% (15mS) rated value it will trip in under 2s, at 100% rated value it will trip under 200mS and at 5 times it's rated trip value (150mA) it will trip no slower than 40mS on both halves of the ac waveform.

Because our earth connection is also the fault path also have to verify the Earth Fault Loop bascally the earth connection has a low enough resistance for enough current to flow under fault conditions to blow whatever over current device is being used.

So our system (basically) has RCD's monitoring the earth potential and circuit breakers covers over current conditions

Matt

MDShunk

Yes way. I'm serious. For the most part, if the breaker doesn't trip when it's energized, everything is assumed to be okay. That's the way it is. It's only larger installations that get any testing at all, and even that's hit and miss. It's certainly never legally mandated, but often in the specs for larger jobs.

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Docara

I'm honestly and completly lost for words!!!!

In a litigation culture like the states surely you line yourself up for, at best, a minor lawsuit or, at worst, a potential manslaughter charge if you cannot PROVE your instalation / alteration is safe when you leave your customers premises? With the best will in the world we all F*** up

So what do you to cover yourself make sure you carry a some sort of professional indemnity Insurance?

Matt

MDShunk

Yes, of course. That, and the installation gets inspected (but not tested) by a third party. The reality is that very darned few injuries, deaths, or property damage are ever linked to improperly installed electrical wiring.

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InPhase277

We don't do a ground loop impedance test, because we don't rely on the Earth as a fault path. Our ground (CPC) originates from the neutral at the first means of disconnect.

I personally don't megger the circuits, but I do remove the bond jumper (E-N connection) and do a continuity test to make sure there are no errant ground-to-neutral shorts.

Of course we carry insurance, and a third party inspection puts some of the blame off on the inspector. But in reality, in a properly installed system, there are very few problems. It is usually only after it has been mucked with by some "jackleg" (term used in the South East U.S.) that problems crop up.

frenchelectrican

Docara.

Speaking of hours for fitting up the 240mm² that about right and that is simauir time I done in France which I do it pretty often the smaller SWA can be done much quicker.

Now term of Megger or Meggered both are refered to testing the conductor insulation resistance test and sometime I will say it megged or c'est meggered.

The 120 and some 208/240 volt circuits useally not meggered but some low amparge on 480Y277V circuits useally not meggered however for larger size it useally done especaily with parallel conductors { I get bad conductor show up from time to time and if you see bad conductor and it will do pretty good damage if not catch in time I have one blow out not too long ago that is a 1600 amp main switch set up}

And the other thing to make it clear to you I do go back and forth between USA and France pretty often so I am famuair with both system and pretty good part of UK reguations however I am not fully 100% famair with Reg 17 but Reg 16 of course but not used very often at all unless I am in UK area then I can deal with it.

And Docara you are more than welcome to France if you have time to hop over and see how our system line up and ditto with North America do it compelty diffrent what UK set up.

Merci,Marc

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Pas de problème,il marche n'est-ce pas?"(No problem, it works doesn't it?)

JvH87

Here an example how its installed in the Netherlands.

3x4x240mm2

Took me about a day to install them.

marty

Hi Guys
very interesting subject, JvH87 that does not look like swa cables used in the UK. How do you secure them to the enclosure??
How do all you guys strip down the swa cable. Is there a tool you use.??

frank

Hacksaw and Stanley Knife. That's all there is

Frank

frenchelectrican

There are few ways you can skin that SWA cable.

Most common is uility Knife and hacksaw or I have homemade rig that will get on the SWA cable and twist it and pull back it will come off like banana skin come off.

Then take the sidecutter to trim as need to.

Oh yeah they do come in either copper or steel earth conductors on SWA.

Merci,Marc

Merci,Marc

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Pas de problème,il marche n'est-ce pas?"(No problem, it works doesn't it?)

JvH87

I cut them with an recipro saw. Then I skin them with this knipex cable knife



I cut the steel armor with an concrete nipper

And the picture was taken without the top cabinet on, in that cabinet are the cable fixtures.

And our SWA cable armor is part steel part copper, we cut away the steel and use the copper as a ground conductor.

marty

JvH87
I assume that the steel that you cut away is in a type of paper/foil material?? Do you attach a gland of some sort??
Frank have you tried the bladerunner from kew technik ??
Would you be interested in tool that cuts into the outer insulation and part way into the steel strands circumferentially and then cuts the outer insulation down in a longitudinal manner???

JvH87

No the armor of the cable is part steel part copper, then comes a layer of thin steel sheet then the foil material. I hope the picture shown makes it a little clearer and what do you mean by gland?



If it aint clear I'll try to make some close up pic's next time

Joe Tedesco

Docara

I will take a closer look at your comments above as soon as I am released from the bunkers.

How do you see this cable here used; is the flat steel wire and ribbon OK as an earth ground for any circuits; or as we call it equipment grounding conductor?

Can you post the correct way that this British Standard system is to be installed and name and identify the supply different systems.

Do you ever allow the neutral to be used to bond the enclosures?

Video about the code changes

Like to have a job in Iraq?