×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

To cross bond or not to cross bond

To cross bond or not to cross bond

To cross bond or not to cross bond

(OP)
Under the current U.K. regulations is it still neccessary to cross bond pipework below every sink in an installation

RE: To cross bond or not to cross bond

Metal pipework under a sink which connect to the taps have to be considered under BS7671 as 'Extraneous conductive parts', therefore, bond them!

RE: To cross bond or not to cross bond

On second reading you state 'every sink',
If you have a line of sinks in a public toilet for example you would not need to cross bond under each, you would however need to make sure that they are bonded such that there is no potential difference between any mutually accessible conductive parts.

RE: To cross bond or not to cross bond

(OP)
thank you sparkyman thats exactly what I thought

RE: To cross bond or not to cross bond

Commercial & Domestic kitchens, cloakrooms, bedrooms and toilet areas which may contain a sink or hand basin but do not contain a bath tub or shower are not among the special locations covered in Part 6 of BS 7671. There is usually no reason why such rooms should be considered as locations of increased electric shock risk requiring the provision of supplementary bonding.

The 15th Edition of the IEE Wiring Regulations required supplementary bonding to be applied to all sinks where extraneous-conductive-parts were not reliably connected to the main bonding, and many examples still exist today. This requirement was deleted in subsequent editions of the Wiring Regulations and it is not required by the present Standard, BS 7671.

Alan

RE: To cross bond or not to cross bond

Suggestion: Essentially, all conductive metallic surfaces are safer to have them bonded since not all of them (not all items) are explicitly covered in standards.

RE: To cross bond or not to cross bond

jbartos,

Try telling that to the window cleaners who have been killed by the touch voltage appearing on earthed metal window frames

RE: To cross bond or not to cross bond

Things like window frames, in particular, which are likely to be at the edge of the equipotential zone really should not be bonded.  Where there is doubt, the if an insulation resistance ("Megger") test shows that it is at least 2Mohm to earth, then don't bond it!

Otherwise, you'll have to start bonding door handles, coat hooks, etc!

Brian

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources