Posted for Eric Monk, intertest.systems...@ieee.org
:-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 (Voice) 619-505-1502 (Fax) Military & Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis :-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) > -----Original Message----- > From: Eric Monk [SMTP:intertest.systems...@ieee.org] > Sent: Thursday, October 07, 1999 5:25 PM > To: WOODS, RICHARD > Cc: emc-p...@ieee.org > Subject: RE: Conduit entry dimensions > > Hi Richard and group. > > ELECTRICAL CONDUIT SYSTEMS IN THE UK. > > Electrical conduit systems in the UK were converted during metrication to > their nearest metric equivalent. > > Sizes refer to outside diameters. > > The more common sizes are 20 mm (3/4"), 25 mm (1") and 32 mm (1 ½"). > Larger than this there is a tendency to opt for metal trunking. > > 16 mm must be based on the old 5/8" conduit which I cannot confirm > is still available in the UK, until I receive an updated catalogue. > > Knockout dimensions are simply a clearance hole for the applicable metric > diameter of the conduit size recommended for the application. > > The preferred method of termination at an enclosure is to cut and thread > the conduit a distance from the box, equal to the diameter of the > conduit. > > Fit an 'internally' screwed coupling (like an oversize sleeve) to > the end of the conduit and secure it to the enclosure with an > 'externally' screwed brass bush inserted from inside of the > enclosure. (bush is the same diameter as conduit thread) > > The brass bush has an hexagonal flange larger than the thread to > tighten onto the enclosure firmly gripping the edge of the knockout > hole between the brass bush and the coupling and providing earth > continuity. > > The inside edges of the brass bush are chamfered and smooth to > prevent damage to cable insulation when cables are pulled through the > conduit into the enclosure. > > Variations are to terminate into a threaded elbow or T-piece if this is > dictated > by space constraints. > (ie. bush thro k/o into elbow - conduit into elbow) > > An alternative is to bring the threaded end of the conduit through > the knockout and secure it in the enclosure with a locknut on the > outside and an 'internally' screwed bush on the inside - but this is > not considered good practice. > > However the termination is accomplished in practice, the knockout > dimensions > are the same - > Close tolerance clearance hole for the diameter of conduit > specified for the application. > > Regards Eric Monk. Technical Director - E M Consulting Ltd. > > INTERTest Systems is the trading name of the test laboratory of E M > Consulting Ltd. > > > ***** Your best support in "TESTING" situations ***** > ***** INTERTest Systems UK ***** > ***** International Product Certification ***** > ***** ONE-STOP-SHOP for ALL testing ***** > *** PO Box 321 - Bucks HP9 1XJ - England - ++44 (0)1494 673438 *** > ***** INTERTest Systems UK is the trading name of ***** > ***** the test laboratory of E M Consulting Ltd. ***** --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
