People's opinion....

[Mr s]

Afternoon to all.....


i have a question to ask all of you and wondered if any of you could help..

I was carrying out some work on one of the other sparks jobs today and questioned why he had three earths at a socket. It is a ring main. Now before you say it it is not a fly lead as it's in plastic dado trunking. Now his reply was that we have been told from now on when using swa to dado trunking to take a tembi clip from the wire sheaf to the socket outlet. I have never heard of this before but I am curious as to what you think. My thoughts where that the sheaf will be earthed via the trunking at the board end with a bolted down banjo and we are using three core so has a core for its cpc.

any feed back would be appreciated..........

 

[Cyril Molony]

it most case the earth bar is the met, especially for domestic installations, I agree in commercial/industrial you may have and external MET, but it may also be incorparated into the consumer unit/distribution board.

 

[Tidy Max]

As a Time Served Precision Engineer I have to say that thing is total cack!!!

I have used them quite a few times and i thought they were decent? They have small serated teeth on the bottom to dig into any metal work they are tightened down on to, they have one grub screw for tightening a crimp into and also an allen grub screw so they don't come loose over time! I much prefer them to drilling out banjo holes!

Wiska also do some earthing connections like these.. although i didn't like the look of them too much!

 

[Andy78]

If it a PVC SWA to BS5467 and you are use one of the core/conductor as a circuit protective conductor then armouring must only be terminated at the supply, (to provide protection against mechanical damage or piercing of the amoured) at the load end it must be terminated into a not conductive box or trunking. This is a requirement of BS 5467 and not the regulation. As it be described, under fault condition most the the fault current will flow through the cable and only a fraction through the armouring, this will produce circulating current, that may cause damage to cable. Read Paul cook commentary on IET regulations.

Why would a BS covering the construction of a particular cable dictate the method of it's installation ? And why would BS7671 which dictates the requirements for cable installation not mention this ?

 

[VoltzElectrical]

I have used them quite a few times and i thought they were decent? They have small serated teeth on the bottom to dig into any metal work they are tightened down on to, they have one grub screw for tightening a crimp into and also an allen grub screw so they don't come loose over time! I much prefer them to drilling out banjo holes!

Wiska also do some earthing connections like these.. although i didn't like the look of them too much!

I'm confused. Are we now saying that piranha nuts are rubbish? I thought the general consensus was that they were the way forward, especially when glanding off into powder coated metal enclosures, as far too few sparks realise that the powder coating is non-conductive and therefore the paint underneath the banjo should be scraped off. The piranha nut does this for you when tightening down onto the enclosure.

 

[southsea1201]

Pirahna nuts are great. I've used them many times and those metal teeth really grind in. If you have loads of joints on a job they are deffo worth buying as they represent a real time saver.

 

[VoltzElectrical]

Pirahna nuts are great. I've used them many times and those metal teeth really grind in. If you have loads of joints on a job they are deffo worth buying as they represent a real time saver.

I've used a shed load of them on a recent job, glanding off into plastic adaptable boxes for continuity of the SWA. Neat job and a lot less fiddly than bolting cables onto banjos.

Good price if you buy the SWA (brand) packs that include the gland, nut, and variety of sized lugs.

 

[Tidy Max]

I thought that was what Geordie Spark was implying, i was sticking up for Pirahna nuts haha i am a big fan of them!