I have found what seems to be a point of inconsistency in '950. Consider an external special purpose connector that can be opened without the use of a tool and carries hazardous voltage. The body is plastic. We would all expect recessed contacts on both mating halves, right? But how recessed is recessed enough?
If you look at 2.1.1.1, it does not insist on clearance, just preventing contact, until you get over 1000Vac or 1500Vdc, and then it only requires clearance, not creepage too. That seems inconsistent with Figure F.12, which can easily be applies to this situation and requires both creepage and clearance. The requirements of F.12 are backed up by the requirements in 2.10.3 and 2.10.4 for clearance and creepage. Q1: So what is our requirement? a) Prevent contact (only) of the 3 different probes in 2.1.1.1 b) Item a) plus clearance and creepage per 2.10.3 and 2.10.4 and F.12? Follow-on questions: Q2: If the answer to Q1 is b), then given that it's hazardous voltage, do we require Reinforced creepage and clearance distances? Q3: What Pollution Degree do we use, given that when closed, the connector is certified as IP54 (which gives us PD I in my opinion) but when open the connector is exposed to the environment (outdoor product). Since PD relates to contamination, I would be willing to apply PD I since the connector spends most of its life closed, but what about during/before installation or during servicing? It's open, but should that short duration exposure count? Q4: If the answer to Q1 is a), what is the justification for only requiring no contact as opposed to enforcing creepage and clearance? Is it related to the fact that the person's finger will only be there briefly, making it unlikely that breakdown of the small gap between the finger and the live part would occur? As always, thanks in advance for your assistance. Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. e-mail: [email protected] web: www.xantrex.com Any opinions expressed are those of my invisible friend. Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
