Conduit around cylindrical structures

[Essex1]

I personally think @dmxrr is doing the right thing. Pyro is a thing of the past except for a listed building so that leaves steel conduit. This is the correct choice. SWA?  Come on?  And since when was doing a running coupler an issue?  

 

[Rob_the_rich]

it would be loose which would affect continuity and possible water ingress

scoobed, I can see how it might affect continuity, but unless you use something like PTFE tape, a locknut on the thread surely won't affect water tightness, there is the same amount of gap between the threads, it is just shifted over so that the thread faces are in contact. And PTFE might affect continuity.

 

[roys]

Ahh running couplings remember them well from my dim and distant past, 22 threads in a coupling plus 2 for milled lock ring equals 24 threads on one side of conduit and 13 on the other side, all our conduit stocks had tape on one side to help us count the turns.

 

[Evans Electric]

scoobed, I can see how it might affect continuity, but unless you use something like PTFE tape, a locknut on the thread surely won't affect water tightness, there is the same amount of gap between the threads, it is just shifted over so that the thread faces are in contact. And PTFE might affect continuity.

Rob  , you can't start making up your own regs . :B ........a runner is as you so accurately described but ALWAYS with a lockring backing it up .

They were something you tried to avoid TBH  because of the double thread ....along with making your own nipples .

And as I said , I don't know if it was a reg. or one of the many urban myths that permeate this trade , but we were told that on one run of conduit you could only use one runner .  It was another one for the Electric Police I think .   There are many unwritten conduit laws that we just seemed to assimilate ...like only two 90 deg. bends , before you insert a box .  If theres too many bends and pulling the cables in is difficult , get your mate to feed them in with wet ,soapy hands , or WD40 or tallow or even the proper stuff (which we never saw) 

Oh theres another memory,  contractors NEVER use solid bends , Inspection bends or inspection elbows & tee pieces .   Always pull your own bend and its always a tee box not an inspection tee piece.  and always B/E tube   ....galvo was for outside only.

By the way , all runners had to be painted ...you had a choice of silver galvo paint or red oxide.

And an electric threader was as rare as rocking horse pooh .......in fact I only ever saw one ..ever .    

 

[Tony S]

By the way , all runners had to be painted ...you had a choice of silver galvo paint or red oxide.

We only used japanned, I had a tin of black enamel paint for the threads and any grip marks on the conduit.

It took me over three years to re-hash a switchroom, all new work was metric with dozens of metric/imperial adaptors, running coupling all over the place. Like any industrial work, if the plants running there’s naff all you can do.

 

[kerching]

How do they get away with calling the new stuff 'black enamelled,'?

enamelling must have a new definition now!...its usually down to bare metal as soon as you take it off the roof rack, put it in a pipe vice and it looks like you have had a knurling tool on it

boughtbsome from CEF many years ago, it was from their 'pre rusted range'! All boxes had to be retapped and all threads re done....total,carp

on a slight tangent, since Pyro was mentioned. CEF MICC glands were not Ex rated a few years ago...not sure about now though. 

The firm that did a local filling station did not realise this...until i did an inspection a few years later

 

[Tony S]

I can see how it might affect continuity, but unless you use something like PTFE tape, a locknut on the thread surely won't affect water tightness, there is the same amount of gap between the threads, it is just shifted over so that the thread faces are in contact. And PTFE might affect continuity.

By tightening the coupling to the shoulder of the short section you stop water ingress from that end. The lock ring tightens the threads on the long section. Water tight unless it gets physically damaged and runners will always be a weak point.

To do the job properly red lead should be applied to the threads, when dry you can tittivate the coupler with the finish of your choice.

 

[Tony S]

How do they get away with calling the new stuff 'black enamelled,'?

enamelling must have a new definition now!...its usually down to bare metal as soon as you take it off the roof rack, put it in a pipe vice and it looks like you have had a knurling tool on it

Its 25+ years since I last did conduit work, the proper “japanned” was good quality.

Would you run galvanised to extend a japanned run that had been there since 1935?

BTW I also reused the VIR if it tested OK.

 

[Blue Duck]

How do they get away with calling the new stuff 'black enamelled,'?

enamelling must have a new definition now!...its usually down to bare metal as soon as you take it off the roof rack, put it in a pipe vice and it looks like you have had a knurling tool on it

boughtbsome from CEF many years ago, it was from their 'pre rusted range'! All boxes had to be retapped and all threads re done....total,carp

on a slight tangent, since Pyro was mentioned. CEF MICC glands were not Ex rated a few years ago...not sure about now though. 

The firm that did a local filling station did not realise this...until i did an inspection a few years later

Wrexham mineral cables is the brand SEF stock I was asked If I wanted ip rated glands?? WTGrape? I thought they were all ip rated... ohh well.

not cheap either.

 

[steptoe]

I personally think @dmxrr is doing the right thing. Pyro is a thing of the past except for a listed building so that leaves steel conduit. This is the correct choice. SWA?  Come on?  And since when was doing a running coupler an issue?  

Since when,?

Properly installed pyro will outlast us all, and the next generation too,!! 

 

[Tony S]

Only those who don’t know how to work with Pyro decry it.

 

[kerching]

Only those who don’t know how to work with Pyro decry it.

Doing a large Data install,a couple of months ago. Fire Alarm muppet arrives and told manager that system needed extending as it did not comply ( strange as it never came up,during any of their annual tests).   And all the pyro,would have to be ripped out as it was illegal to join 'soft skin' to MICC!

i just kept quiet carried on with the Data.

 

[Evans Electric]

As I said above .........there are more myths & legends in our trade than Lord of the Rings.

Contiuing the conduit subject ,  we had a couple of subbies helping with a hospital ward refurb job .  Basically trunking & conduit to be hidden above a suspended T bar ceiling .

Black enamel conduit being installed ....I brought 20 odd galvo tee boxes we had in stock ...just use them up on this job , been on the shelf for 6 months .

The one guy couldn't cope with them clashing with black conduit ..." You can't mix them " he came out with .  " And they look dreadful "  

Never be seen above the ceiling , just use them up .

I learned later that they had been fitted and he'd painted them all with black paint from home . :C

 

[Essex1]

Since when,?

Properly installed pyro will outlast us all, and the next generation too,!! 

So will anything if it is properly installed. 

 

[Essex1]

Only those who don’t know how to work with Pyro decry it.

I have very limited knowledge on pyro. Installed probably about 20 meters and made of 4 ends. That is that. However; it is a fact that it is hardly used these days compared to alternative methods. I know electricians like to flex their muscles with things like this but I prefer to just say it as I see it.  

 

[Sharpend]

It has to be said though, properly installed pyro is a work of art, it is also a fairly discreet cable so lends itself to being able to blend into the background. 

 

[Essex1]

It has to be said though, properly installed pyro is a work of art, it is also a fairly discreet cable so lends itself to being able to blend into the background. 

Agreed. I do like a good bit of tray and trunking work also though. 

 

[Tony S]

I have very limited knowledge on pyro. Installed probably about 20 meters and made of 4 ends. That is that. However; it is a fact that it is hardly used these days compared to alternative methods. I know electricians like to flex their muscles with things like this but I prefer to just say it as I see it.  

The reason it is rarely used now is expense and lack of ^knowledge^.

If we consider the job in question, bending conduit to the form of the walls will take time. Total the cost of that time and materials and compare it to the cost of Pyro with its speedier installation.

If a job specification stated MI cable throughout would you:

A/ Turn the job down.

B/ Learn how to work Pyro.

C/ Subcontract the job.

 

[dmxrr]

It's the big micc I enjoy looking at, it's incredible to see, ripped loads of it out at Llanwern. 

Can't even imagine wrestling with a 1H240 

 

[Essex1]

The reason it is rarely used now is expense and lack of ^knowledge^.

If we consider the job in question, bending conduit to the form of the walls will take time. Total the cost of that time and materials and compare it to the cost of Pyro with its speedier installation.

If a job specification stated MI cable throughout would you:

A/ Turn the job down.

B/ Learn how to work Pyro.

C/ Subcontract the job.

As I said earlier this is reletively easy to do. Quicker than pyro. 

From your choices A and C are no option. Of course it would be B. We have a skilled pyro man on board anyway. I was talking about myself as opposide to the business.