Piranha Nut in MK Masterseal Box

[RF Lighting]

I was nearly right

It was "earthing nuts" who are a competitor to piranah who advise this:

The design also includes a number of cutting teeth formed on one surface of the nut. These teeth cut into the enclosure wall, preventing the nut from turning and enabling the gland to be tightened to the nut from the outside with only one tool. Where this feature is not desired, the nut may be reversed and tightened to the gland instead.

 

[GaryMo]

Either way, they're great invention.

I've used them with the toothed edge down in both metal and plastic enclosures with great success.

 

[333rocky333]

Rocky, have you got the piranha nut on the wrong way?
Shouldn't the serrated edges not be there to bite (piranha!) into the backbox which causes the locknut to hold in place?

I know it's only a mock-up before you say!

Either way round I have used them.
I done it that way to show the teeth, for people that have not seen them.
When theres room i prefer to make the gland up first then spin the nut on.
With a metal box I would tend too try to use the teeth for better contact.

 

[BigJon]

Anyone know the rough price of these nuts over the trade counter.
Just curious
Cheers.

 

[333rocky333]

They are packs of 10, about £1.50 each I think.

I was nearly right

Pirahna stated the same at first.
Still do on some sites
http://www.qvsdirect.com/20mm-Piranha-Earth-Nut-pr-19729.html

 

[ban-all-sheds]

The teeth are also useful for cutting through the paint on metal enclosures.

 

[333rocky333]

The teeth are also useful for cutting through the paint on metal enclosures.

I know a site, where at least 3 pyro cables not earthed due to terminating in Black enamel 4 x 4 boxes with black enamel lockknuts.
We quoted to disconnect them and fit Pirahna nuts for that same reason,have used them a few times as a more superior locknut, regardless of the cost as the company pay.
Job possibly never did get done.

 

[NotHimAgain]

The teeth are also useful for cutting through the paint on metal enclosures.

I know a site, where at least 3 pyro cables not earthed due to terminating in Black enamel 4 x 4 boxes with black enamel lockknuts.
We quoted to disconnect them and fit Pirahna nuts for that same reason,have used them a few times as a more superior locknut, regardless of the cost as the company pay.
Job possibly never did get done.

I quoted for that job using using these:
http://www.tonesties.co.uk/Product/3051/serrated-washers.aspx
and these;
http://www.tonesties.co.uk/Product/3048/brass-earth-tags.aspx

A bit cheaper.

Piranha nuts are good, but not so good that they justify that price difference for an MI termination

 

[ColJack]

don't you lot use a gringing cutter when drilling your boxes?
it has a file like ring around it's base and takes the paint off quite well..

any why don't they make the banjo's with a crank on them.. how are you supposed to get a screw under it without drilling the box?

 

[ban-all-sheds]

1) They bend easily, if you want.

2) I thought the idea was that you were supposed to drill the box?

 

[ColJack]

not if it's waterproof and / or threaded.. if you're not reliant on the SWA as the earth and you only want to ensure continuity such as on motor isolators outside then you can just link the banjo's with a screw and nut..

they aren't that bendy and I've snapped more than one when trying to crank it to take a brass M6 bolt..

if you do have to drill it to a plastic box, then you're sandwiching the plastic between the nut and the bolt, so you've got something squishy in the connection..

 

[Spark123]

I have come across the cpc soldered to a shortened banjo to save space which seems neater than trying to mess about with crimps, nuts bolts etc.
I don't like the idea of compressing a banjo onto plastic too, it is better to use two locknuts on the inside with the banjo between them.