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 37 subscribers
  • Views 1657 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

single phase PEN protection within three phase supplies

David Slate

Good Morning all,

We have used MATTe devices many times for PEN protection when the charger has no inbuilt protection. 

The MATTe devices for single phase rely on protection settings as described in indent (iv) of 722.411.4.1

MATTe sate on their website the following:

 BS 7671 does not permit a protective device as described in indent (iv) of Regulation 722.411.4.1 to be used to protect single-phase charging equipment in three-phase installations.

Quite a few devices rely on ident (iv) but other than MATTe non of them highlight this issue?

What im after if anyone would be so kind, is an explanation as to why this is the case, and why a single phase MATTe can be used on a single phase supply on a terraced house where next door will be (most likely on a different phase of the same supply) but not within a 3 phase installation.

I have an idea it is due to unbalanced 3 phase loads  and voltage to neutral on one phase can appear to be ok masking any loss of neutral should it occur. But a better explanation would be great!! maybe even links to a diagram to be able to show to project managers!

Parents
  • 0

    If you want a diagram try this thread:  RE: Open PEN detection for 722.411.4.1 (iv)

    As Mike says, the same problem is present on 1-phase installations fed from 3-phase public supply, the difference is that without access to the other phases it's much harder to find a better alternative.

       - Andy.

Reply
  • 0

    If you want a diagram try this thread:  RE: Open PEN detection for 722.411.4.1 (iv)

    As Mike says, the same problem is present on 1-phase installations fed from 3-phase public supply, the difference is that without access to the other phases it's much harder to find a better alternative.

       - Andy.

Children

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