The IET is carrying out some important updates between 17-30 April and all of our websites will be view only. For more information, read this Announcement

Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 24 replies
  • Subscribers 31 subscribers
  • Views 3035 views
  • Users 0 members are here
Options
You may also be interested in
This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

BS 8436 Cable

Jonesy
Hi all I am new to the Forum.


I have a question regarding BS 8436 Compliant Cables. I am aware iof the requirement to protect circuits wired in BS 8436 Cables with "B" Type devices etc due to the requirement to limit fault current in the event of the cable being penetrated by a nail or a screw. However, what if you install the cable clipped direct to the surface and on Cable Tray or basket where the risk of accidental penetration is very low, would it them be acceptable to protect the circuit with "C" Type devices?


I have hunted high and low on the internet for an solution but have failed to find a definitive answer.
Parents
  • 0

    pww235:

    It doesn't really matter what they serve does it?


    The key constraints are the required circuit breaker type/rating, the limitation on available conductor sizes and the installation method information available from the manufacturer.


    P




     

    Of course it matters what they serve, presumably the connected equipment HAS TO BE protected by a a Type C MCB  because it has an inrush current that would trip a Type B MCB.


    Or are you applying some unwritten rule that in commercial installations Type C MCBs are used, because that’s the way it’s done?


    Also if the cable is in a safe place within the cable tray why does it need any armour or earthed protection at all, unless it needs it when it drops out of the tray to the connected equipment?


    I presume this is going to be some cable choice based on the colour of the sheath available rather than what the cable is actually designed for, in which case you drop the spec done to some white sheathed low smoke twin and earth cable, the customer won’t know the difference when they are stood looking up at it.


    Andy B
Reply
  • 0

    pww235:

    It doesn't really matter what they serve does it?


    The key constraints are the required circuit breaker type/rating, the limitation on available conductor sizes and the installation method information available from the manufacturer.


    P




     

    Of course it matters what they serve, presumably the connected equipment HAS TO BE protected by a a Type C MCB  because it has an inrush current that would trip a Type B MCB.


    Or are you applying some unwritten rule that in commercial installations Type C MCBs are used, because that’s the way it’s done?


    Also if the cable is in a safe place within the cable tray why does it need any armour or earthed protection at all, unless it needs it when it drops out of the tray to the connected equipment?


    I presume this is going to be some cable choice based on the colour of the sheath available rather than what the cable is actually designed for, in which case you drop the spec done to some white sheathed low smoke twin and earth cable, the customer won’t know the difference when they are stood looking up at it.


    Andy B
Children
No Data

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines