Right or Wrong - Termination of SWA - Opinions and Suggestions please guys!!!!!

[harrison2987]

Above is a picture of 2 16mm SWA cables terminated into a termination block. In my opinion this is the correct way to dress in the SWA and terminate it into the incoming side of the termination block, not putting it into the same termination as the outgoiong cables.

Is there a reg that says you have to terminate like this? Or is it just good practice to do so??

Below is how another spark has terminated the 2 SWA cables. He has gone straight into the top of the termination block, into the same terminations as the outgoing cables.



Just to be clear there are no fuses on this termination block, it is simply a through termination, i just want to know which way is corrct or better practice and if there are any regs to say which is the better way to terminate.

Thanks in advance for your opinions and help!!!!

 

[shanky887614]

You are correct regarding nominal voltage to earth but it was a very recent re-wording from the red book which included between phases yet doesn't get highlighted at the front as a regulation that has been amended so plenty including myself got caught out by the change, caution on your advice this warning notice is within a control panel and that has its own EU regulations and legislation and doesn't fall within the BS7671

what regs cover control panels?

im curious as 90% of the work the company does is bms/access.

 

[Darkwood]

what regs cover control panels?

im curious as 90% of the work the company does is bms/access.

Ill dig them out next time im back home, their was a lengthy thread last week where i posted the relevant EU regulations that cover control panels and systems although it was a general briefing there are numerous focused regulations specified for different types of systems and machines ...the list is lengthy.....check out appendix 1 several section within apply to machinery controls etc.

 

[harrison2987]

@Harrison... you say the swa's are so big due to volts drop... how long is the run to see such a large increase of csa and whats the front end device rating.... im confused as to why you have taken such large cables into the panel as opposed to a local isolator or socket point with reduced size control fly lead hence you only have a 2,5mm cable incoming to control board. Seems overkill and even if the swa is correct for volts drop you don't have to terminate them direct.... if the run was longer you would in theory end up with cables you couldn't even fit into the panel never mine terminate them.

The runs are between 50 - 100mtrs, we had an electrical engineering and design company calcualte voltage drop and appropriate cable size.

Also the work is in a tunnel with the main contractors specifying what they did and didnt want - hence why we didnt use local isolation or sockets - they are very strict with what they want/dont want.

And yes, if the run was longer we would indeed end up with cables too large to terminate, in which case we would use a transition box or something similar to drop the cable size down before it entered the panel. In this case however the powers above must have thought it ok for the 16mm's to come directly in.

Hope this answers all your queries : )

 

[harrison2987]

Thanks for your opinions guys, nice to know what you lot think.

I agree, a local isolator or something similiar for the SWA's to go into first,then a smaller cable out to the board would have looked ALOT nicer, but we follow designs and orders from above. My voice may be heard but not always listened too. I'm sure some have you have been in that situation before!!!

Anyway thanks for the input

 

[44ALLAN]

Sounds like your hands are tied mate.

I'm guessing front end fuses are 50/63 amp? ( guessing) and if that's the case those cables should have,at least,gone straight into fuses/mcb and not into connector with 2.5mm.

16mm joined to 2.5mm doesn't sit well with me I'm afraid

 

[Engineer54]

I still think some means of local isolation should have been provided on such long supply runs, especially if these cabinets are all installed in tunnels. I hope they aren't confined space type tunnels?? lol!!

 

[snowhead]

Ill dig them out next time im back home, their was a lengthy thread last week where i posted the relevant EU regulations that cover control panels and systems although it was a general briefing there are numerous focused regulations specified for different types of systems and machines ...the list is lengthy.....check out appendix 1 several section within apply to machinery controls etc.

From the Extra Start stop 415v thread;

Safety of Machinery-
EN 292 (ISO 12100 pts 1 & 2) Basic concepts, general principles for design
safety related parts of machinery and the general design principles.
(this references many other standards and outlines all basic principles)

EN 60204-1 (IEC 60204-1)
Electrical equipment of machinery -pt 1 general requirements.

(this is a very important requirement that outlines recommandations for safety related aspects of wiring and electrical equipment on machines)

 

[Darkwood]

Cheers Snowhead saved me a job

 

[PEG]

Fair-play to you,Harrison,you made a suit out of Panda skin and went straight to a Paris fashion show! Break-outs and shrink would have greatly improved an mediocre panel design though...:43: