Useful to know.
In my case there will be 150x150mm trunking at top/bottom and almost certainly I will be using tri-rated cable, probably 70mm, for the connections though I was also considering parallel 50mm just to make routing & bending radius, etc, easier everywhere when pondering 95mm.
I'm guessing the PP41603X is the matching MCCB for 160A. Do you know if there is a direct connection option for feeding it?
In my case its coming off a fused-switch not far away so no need for a incoming switch/breaker on the panel.
If it is TT then you can use the armour of any of them as CPC but will almost certainly need an up-front delay RCD at the sub-main feed point to allow disconnection on a fault.
If TN-C-S then the bonding size of (typically) 10mm copper equivalent can be an issue for many SWA cables as it...
We are looking for a distribution board to provide 3 * 160A three-phase feeds, but they are basically redundant supply path options so max total is 160A as well. I had been looking at using a Hager MCCB panel (as we generally have been using their MCB DBs) but many of them are limited to 125A...
Its not good, but as @westward10 already said it should be on RCD anyway.
Totally aside from the impact on OCPD based ADS, extension leads are one of the things that most need RCD protection, either at the CU or in the form of an RCD plug, etc.
While the ISITEE guide has limits, the reality is this is a production item that meets the various standards and is a damn sight safer than someone joining up 3 * 15m reels!
Not a reliable indication of a fault!
What RCD characteristics (and also why is an incomer needed here)?
Have you done a global L+N IR test to see if there is anything like a N-E fault?
Secondly how big is this installation? I.e. total current and types of loads used?
Some things like large LCD displays or computer servers have a few mA or leakage anyway, so if your installation has a thousand of them you might have a simple answer!
Firstly how are you measuring the leakage?
If you have a clamp ammeter around 3P+N then 5A is indeed quite a concern and probably indicates an insulation fault such as N-E short.
However, if you are clamping the whole SWA cable, or the main earth conductor, then quite probably it is just PME...
There can be a few reasons for low L+N -> E readings:
Connected equipment is leaking. By design, or just old/damp
SPD are connected (but there you get a big difference between 250V where usually > 10M and 500V where usually < 0.1M)
Cable has degraded or is very damp
Accessories are damp/dusty...
The point is you cannot allow a set of cables rated for 70C operation to be heated by those happy to run at 90C, so if you are looking at a section for that group, you should treat them all as if they were rated at the lowest temperature (e.g. 70C) when calculating and if you get an acceptable...
Yes, last one ought to be C2 from BPG#4:
Circuits with ineffective overcurrent protection (due, for example, to oversized fuse wire in rewireable fuses)
However, it has been mentioned before that an "unsatisfactory" judgement could be based on a lot of poor C3 factors combined, rather than one...
Good to hear. This forum is one of the worst sites of any I actually want to visit, but many other sites are still simply intolerable these days without some sort of blocking.
I would be surprised if T&E is not able to deal with the 3P voltages as each core is rated to at least the nominal Uo to earth, and as that is between conductors they see nothing different. Even between the two lives on one side of the CPC in 3&E cable there is now double the thickness of...
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc
Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.