Tails into metal switch fuse

[Gazthesparky]

I've got a job where I'm running a Swa sub main to a 17th edition board. I've got to put a switchfuse by the meter and I'm intending to run tails from the meter into it.

Previously I've put a male bush and locknut in the bottom and run the tails into that but I'm after other ideas that give strain relief.

I've seen the wiska tails stuffing gland but it's expensive at about 20 quid a pop

Any other ideas ? Suggestions

Cheers

 

[davesparks]

If the connection has been made it must be electrically and mechanically sound, regardless of whether it was necessary in the first olace

 

[marc8]

so whats wrong with the above then as we are not even required to fit the fly lead as we have a termination point all ready installed & are already earthed through our earth cable contained within?
this is what we have installed to conform with cable entry not really anything to do with earthing, personally i am happy with it i have a seen a ****e load worse with no glands just being made off in consumer unit.

 

[marc8]

If the connection has been made it must be electrically and mechanically sound, regardless of whether it was necessary in the first olace

so whats not sound or mechanically sound the self tapper? maybe i should have a word with the tacker as he is holding a lot of weight with a similar fixing (in less metal than me) & that might fall on someone & actually hurt them, what your saying is that the self tapper could under circumstances become loose & therefore not be sound, inside a trunk that the cable only just sits inside.
bit over the top

 

[shanky887614]

so whats wrong with the above then as we are not even required to fit the fly lead as we have a termination point all ready installed & are already earthed through our earth cable contained within?
this is what we have installed to conform with cable entry not really anything to do with earthing, personally i am happy with it i have a seen a ****e load worse with no glands just being made off in consumer unit.

dont worry dave is just trying to make you bite, if the armour is not used as the earth technically it just needs connecting at one end

 

[marc8]

dont worry dave is just trying to make you bite, if the armour is not used as the earth technically it just needs connecting at one end

why ? ....

 

[Leesparkykent]

Davesparks is correct though #76. Reg 134.1.4 every electrical joint and connection shall be of proper construction as regards conductance, insulation, mechanical strength and protection.

 

[davesparks]

so whats not sound or mechanically sound the self tapper? maybe i should have a word with the tacker as he is holding a lot of weight with a similar fixing (in less metal than me) & that might fall on someone & actually hurt them, what your saying is that the self tapper could under circumstances become loose & therefore not be sound, inside a trunk that the cable only just sits inside.
bit over the top

I have no doubt about its mechanical soundness, it's the electrical soundness I would question.

 

[marc8]

so whats not sound ? termination point is tight & you have to use a tool to undo the unit & then a tool to undo the self tapper ?
sorry as for the electrical part whats not sound its secure ?

 

[davesparks]

Davesparks is correct though #76. Reg 134.1.4 every electrical joint and connection shall be of proper construction as regards conductance, insulation, mechanical strength and protection.

They've changed it! It's been 'electrically and mechanically sound' since at least the 13th edition and now they think it needs changing? Just another unnecessary change to fill out the list of changes to make the new amendment seem justified.

 

[shanky887614]

I have no doubt about its mechanical soundness, it's the electrical soundness I would question.

then what about the tek screws holding the gland plate to the fuseboards you use? do you drill them and use bolts?

if it is mechanically sound then it has to be electrically sound, it doesnt need the csa as its not being used as a cpc

 

[davesparks]

so whats not sound ? termination point is tight & you have to use a tool to undo the unit & then a tool to undo the self tapper ?
sorry as for the electrical part whats not sound its secure ?

But is it making good electrical contact? Is it maintaining enough contact pressure? The problem is that a screw will not stretch and maintain contact pressure in the same way a bolt will.

 

[shanky887614]

But is it making good electrical contact? Is it maintaining enough contact pressure? The problem is that a screw will not stretch and maintain contact pressure in the same way a bolt will.

it doesn't matter, he is just using a tek screw to secure the cable not for the cpc which is integral to the cable under the armour

 

[davesparks]

then what about the tek screws holding the gland plate to the fuseboards you use? do you drill them and use bolts?

if it is mechanically sound then it has to be electrically sound, it doesnt need the csa as its not being used as a cpc

No, I usually remove the gland plate and bolt a piece of trunking to the board with a paxoline plate between them and bolt an earth to the trunking.
Or if using the gland plate I normally use piranha nuts these days with an earth connected.

Being mechanically sound doesn't necessarily mean it is electrically sound.

 

[Leesparkykent]

I bolt a fly lead on to the gland plate as don't like relying on the screws of the gland plate. Just something I was taught as an apprentice and old habits die hard.

 

[Darkwood]

it doesn't matter, he is just using a tek screw to secure the cable not for the cpc which is integral to the cable under the armour

I would argue it actually does matter hence the regulation as stated in post 81, consider a fault from phase core to swa then it will return on one of 2 paths which may be the tek screw fixing which may have to withstand 1000's of amps in a pulse before the OCPD hopefully operates, better to isolate that end than to make a poor joint that way you ensure the fault current will travel down the correctly glanded end.

As lee points out any removable glanding plates or metal enclosures which are not one solid contruct require earth tails as you should not rely on the fixing screws.