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
  • Replies 11 replies
  • Subscribers 37 subscribers
  • Views 1107 views
  • Users 0 members are here
Options
You may also be interested in

Overload device negate requirement for In<Iz?

E95

Hi all,

For context this is a TP, N & E socket circuit supplying a machine. The machine supplier has recommended that the circuit be supplied from a 125A MCB, however the machining cabling is not supplied from a cable rated to 125A.

I'm being told that a cable size doesn't need to be sufficiently sized for the upstream breaker, when there is an overload unit downstream and that the cabling would withstand a short circuit disconnecting quickly

Is this true? I can't find anything explicit in the regs confirming either way, aside from Ib<In<Iz

Parents
  • 0

    Please note amendment 4 will see regulation 433.3 updated - it appears you won't be able to omit overload protection as easily. 

    Although what's in the DPC isn't necessarily what'll end up in the final version ... there might be some debate about this one - outlawing unfused spurs from ring finals and having to cable industrial motor circuits for the full starting current, might ruffle a few feathers....

       - Andy.

Reply
  • 0

    Please note amendment 4 will see regulation 433.3 updated - it appears you won't be able to omit overload protection as easily. 

    Although what's in the DPC isn't necessarily what'll end up in the final version ... there might be some debate about this one - outlawing unfused spurs from ring finals and having to cable industrial motor circuits for the full starting current, might ruffle a few feathers....

       - Andy.

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