Still remember one of my first big jobs as an apprentice. Trunking in the risers has the lid held on with cable ties and was so warm it was uncomfortable to touch, and that was before the building was in use. Might have been something to do with the rings being wired in 4mm.🤣
I used to work in a building that had quite low ceilings, with cable tray crammed with coax and Cat5 data cable, down the corridors. Every time a new system was installed, they hung a further cable tray under the existing one, as nobody dared take out any of the obsolete cabling!
Biggest problem I THINK we have in this country with regard to the regs; Leaves to much up to the installer. They seem to be able to interpret what they read. Had a question for a few sparkies I worked with. Hypothetical of course. "If you had to cable an appliance and you had taken ALL of the precautions, taken account of ALL of the considerations like disconnect time etc, and carried out ALL of the calculations necessary to determine the max current pulled and it turned out to 99A. Would you use cable rated to carry 100A. None would/could answer.
That's for an electrical engineer to figure out... I'm no electrical engineer but I'd still be asking more questions. How long is the run? Is that cable rated 100A @ 75C or 90C? What is the duration for which max current is pulled? What is the typical current actually expected to be? Cause frankly depending on the answers to those it can be either yes or no and still be a perfectly fine system. Am I cabling directly from a breaker or adding to an existing system? What is the likelihood of this system being modified in the future and requiring more power? Sure someone could give you the stock "no, your breaker would need to be rated for 125A because of the 80% rule. your breaker protects your wiring therefore your wiring must also be 125A. most breaker terminals are rated for 75C and therefore the wire must be 125A @ 75C and not 125A @ 90C unless you know for damn sure the breaker's terminals are rated for 90C" but that could just be unnecessary cost without asking further questions.
