Crimps inside the CU

[SPARTYKUS]

Sedgy you just made it 44 :tt1:

 

[sedgy34]

That don't count it wasn't a nonsense answer like
"der I want to see heat shrink all the time even when I see other people's jobs" whatever :nopity:

 

[Amp David]

Would rather use a connector block in a CU than a Wago. Takes up less space and will look neater.

Personally if there are a few to extend then lets use a DIN rail enclosure with DIN rail terminals and extend in that.

Job Done!

 

[JulianC]

I use Wagos, then heatshrink them. Twice. Neat and bulky - what more can you ask for?

 

[electric will]

I use Wagos, then heatshrink them. Twice. Neat and bulky - what more can you ask for?

Heat shrink on a wago?

 

[JulianC]

Heat shrink on a wago?

Errm, no. I was not being serious. :sad_smile:

 

[electric will]

Sorry, bit early brain not in gear yet.

 

[SJD]

All this talk about crimps and Wagos, nobody has mentioned choc blocks!
I've come across choc block connections made in a CU a few times now, but I guess nobody on here will want to be doing that.

 

[Marvo]

Choc block connectors are still all the rage for domestic and commercial electrical work where I am. They don't generally give problems more than any other connection if it's a good make and if the joint is made correctly.

 

[JulianC]

Crimps, Wagos, choc blocks. It's all down to personal preference at the end of the day....

 

[Amp David]

All this talk about crimps and Wagos, nobody has mentioned choc blocks!
I've come across choc block connections made in a CU a few times now, but I guess nobody on here will want to be doing that.

Check out post 48:nono:

 

[Darkwood]

Il jump in now with my take .... During the war (falklands) we were taught that standard crimping with a good quality ratchet crimp was fine for stranded cables as the cores will move to the specific shape of the crimp and give a good sound joint, crimping solids in this way does not give a sound crimp as the solid resists the shaping of the lug and deforms around it leaving air pockets and what may seem to be a good crimp it can fail quickly with a bit of manipulation.

Where you require to crimp solid cores then solder or a specifically designed crimp needs to be used including crimp tool that shapes the crimp around the circular core without deforming its structure, leaving air pockets or leaving a weak joint.

As the joint is within an enclosure if the crimps are insulated and made off correctly with cable insulation up to crimp butt then there is no requirements to sleeve it in any form as the crimp insulation gives adequate overlap in this situe.... the only angle you could address is colour coding of crimps in relation to cable designation which IMHO is causing anyone any confusion over the identity of the cable then they shouldn't be in that board in the first place..... having said that it is an extra touch and more professional look to heatshrink a correctly colour coded sleeve on them but been within an enclosure their is no requirements for more than one sleeve if you decided to go that way.

Note! I have crimping tools for both stranded and solid core and they crimp in a totally different way.

 

[Engineer54]

crimping solids in this way does not give a sound crimp as the solid resists the shaping of the lug and deforms around it leaving air pockets and what may seem to be a good crimp it can fail quickly with a bit of manipulation.

Which is exactly what you want, the solid core being de-formed within the crimp!! There will be air pockets within any type of crimp connection/cable type.

I test a percentage of all the crimped connections on any panel i'm inspecting, i'm rarely able to pull a solid core cable out of a crimp. But i will state here, that all of the good quality crimping tools used on the projects, are calibrated on what is, a regular basis....

 

[Darkwood]

Which is exactly what you want, the solid core being de-formed within the crimp!! There will be air pockets within any type of crimp connection/cable type.

I test a percentage of all the crimped connections on any panel i'm inspecting, i'm rarely able to pull a solid core cable out of a crimp. But i will state here, that all of the good quality crimping tools used on the projects, are calibrated on what is, a regular basis....

Air pockets create a few potential problems firstly its a sign the crimp hasn't formed properly so you cant be 100% sure it will give a good service life if you overcrimp a cable or use incorrect crimper you may find this occurs, secondly if air pockets are created and especially with regards to stranded cables its possible for a % of the strands not to be correctly gripped which would create a weak link in the CCC of the cable, and lastly you may notice that some crimps like through-crimps have whistle holes as this is not as many believe to see your cable is fully in but to expel the air as you crimp.

I dont want to contradict your methods or teaching or experience but this is the way we were taught, if for any reason you had a trapped air pocket in the crimp then any heating of the crimp which may be caused by its own poor crimp method will cause the air to expand warping/buckling the crimp thus exagerating the issue. When crimps are designed and manufactured they are made as so to expell any air pocket trapped within the crimp and yes air will always exist trapped but at a acceptable level not to contribute to the failure of the joint.

I know this is about your basic 1.5, 2.5 thru-crimps but this issue becomes a real problem when moving on to big cables to ensure the crimps are done correctly, ive seen lugs fitted where they have been overcrimped and ive seen these fail when in service although sometimes it can take yrs it still causes massive problems, ive also seen appretices using £1 crappy market crimpers and arguing they are good enough and this is why colleges should stop fast tracking courses its not all about knowing how to wire a house and with all due respect im sure you already know that.

If there was a reg, or method to learn then we were taught why the reg or method existed in the first place

 

[Engineer54]

A lot of over thinking and over worrying going on here. The real basics of making a good crimped connection, no matter whether the cable being crimped is stranded or solid, is the use of respected crimps and a good quality crimping tool and maybe, someone that knows what they are doing!! To be honest, i can't say that i've seen failed crimps due to trapped air pockets, as you say the better quality crimps will have the whistle holes allowing air to be expelled...

As stated i'm not a great lover of those bulky PVC insulated crimps or particularly the crimping method either. You can't beat IMO, uninsulated crimps using an indent type crimping tool on solid cored cables, with heat shrink over the crimp and an over cover heat shrink of the appropriate conductor colour. I don't mind the heat shrink insulated crimps either, with again a colour matching over sheath heat shrink...

Not sure how you can over crimp the larger sized lug crimps, as the usual hydraulic type crimping tools crack at the correct crimp pressure?? Unless the crimping tool itself is faulty, or the wrong crimp and/or die size has been used, seen that a few times ...lol!!!