> Happy Holidays group, > > In getting agency approval on our I.T.E. product, the safety ground terminal > has come into question. > When hard wiring a product, Para. 3.3.7 indicates that the conductor is to > be clamped between metal surfaces, and the terminal shall not damage the > conductor. This has been interpreted as the terminal must have a metal plate > that clamps down on the conductor, and no rotational stresses from the screw > are applied to the conductor.
Hi James, Not clear what the problem is here. "Rotational stresses"? Is the conductor being visably damaged by your terminal? If not, sounds like someone's getting a little overzealous. The clamping plate you refer to is used to secure the conductor - not to prevent "rotational stresses from the screw". Additionally, European standards such as EN60947 recognize, and even contain drawings of the type of terminal you describe - without clamping plates. Problem is, if you show this to your agency, they may decide they want to carry out testing according to the requirements of the standard (EN60998/999 are probably more appropriate in this case). Rather than worry about "rotational stresses" - I would be more worried about long term security. Is it really a screw terminal, or is it a stud (bolt) terminal? In the case of a screw type terminal for PE, I would generally expect to see a stud terminal with a bolt, a clamping plate, and a spring (lock) washer. If you feel confident about your terminal however, crimp a terminal lug to the conductor. This should solve your problem with the agency about "rotational stresses". > In Europe, I understand that a rail terminal block, where one of the > terminals is shorted to a rail, is generally used, and accepted, but > somewhat costly. There may also be alternatives, but we haven't found an off > the shelf one yet. "Somewhat costly" is an interesting expression. I've heard this and "relatively expensive" both offered as reasons when designers don't want to change their design. Can anyone give me a rough idea (perhaps as a percentage of unit cost) of what "somewhat costly" mean? > I am looking for a grounding terminal that accepts #14-#18 AWG wire, has a > clamping plate, is tin plated, and has a mount or hole for direct connection > to a chassis. Most of the approved terminals I know of are for rail mounting (DIN...). Don't think it would make too much sense to install a rail just for one PE terminal. If you're looking for rail mounted terminals however, check Weidmueller and Wago. Both companies offer PE terminals that can be snapped onto a carrier rail. Worth a look if you're including many terminals in your equipment. Good luck, Matt --------- 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).
