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 9 replies
  • Subscribers 36 subscribers
  • Views 2476 views
  • Users 0 members are here
Options
You may also be interested in
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Distribution board overload conditions

E95

Hi all,

I have a question regarding how overloads are protected against in distribution boards

For example, I have a 400A distribution board fed from a 400A MCCB, I assume that the distribution is rated for the full 400A continuously? Interestingly OMS made a comment on how distribution boards were constructed with a 0.6 diversity included so that a 400A board is actually only rated for 240A continuous, someone disputed this but there was no other response unfortunately.

Not to digress too far, assuming the thermal overload component doesn't start to operate until 600A what is protecting the board from an overload condition? Is this supposed to be by diversity calcs only?

I assume if this was the case there would be lots of incidents involving burnt switchboards, or the more obvious answer that the 400A board can take 600A for longer than it would take a typical protection device to operate?

Thanks for any responses Thumbsup

Parents
  • 0

    Indeed, and a 400A board protected by a 400A fuse or 3 400A fuses if 3 phase, would be a set up that requires no further protection against overload unless there is something non-standard  going on that changes things so it needs some de-rating, like it is to be used in a desert or a the hot part of a steelworks !

    Mike,

Reply
  • 0

    Indeed, and a 400A board protected by a 400A fuse or 3 400A fuses if 3 phase, would be a set up that requires no further protection against overload unless there is something non-standard  going on that changes things so it needs some de-rating, like it is to be used in a desert or a the hot part of a steelworks !

    Mike,

Children
No Data

Community Rules & Guidelines