IEC60730 and "normal use" - Page 1
Forum section: electronics / projects

author: poorchava
author_rank: Super Contributor
timestamp: February 21, 2020, 08:38:35 am
content: Hi,I'm sure, that many of you have had to do with IEC 60730 / EN 60730 when designing stuff. We're currently designing one, that falls under that norm.As with most norms, it's extremly broad, and identifying which clauses apply to particular device is quite hard.We have a product, which is essentially a building automation control box. It's just a plastic IP-rated enclosure with some cable glands for connecting wiring. The thing has a plastic cover fixed with screws, but no buttons/displays etc on the outside. On the inside there is a PCB which has terminal blocks, power supply and some interface stuff (display, buttons etc). In general the user/installer has to unscrew the cover change settings, which is a rare osccurence. Obviously, the control parts that the user will touch are separated from mains byt a transformer / relays, but there are some live parts like terminal blocks, fuse holders and such.The problem we have is, that the norm requires that the device be safe during normal use (duh!) and the normal use is defined in following way:QuoteNow, our logical interpretation would be, that if the device is designed to generally be left alone and do its job 24/7, and be opened only for service or change of configuration, this falls under the Note 2, and as long as the manual says "don't fucking touch this and that when you change settings", we are compliant.The difference is, that if we need to make the live stuff inside inaccessible, then we need to factor in cost for injection molding a special cover, which we obviously want to avoid.The use case is quite common I think, and I haven't seen any similar device have any cover over live parts inside, but those products may just not be fully compliant with the norm.Can you maybe share your experience with that?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 21, 2020, 09:21:52 am
content: Quote from: poorchava on February 21, 2020, 08:38:35 amHow about vacuum forming - much cheaper tooling.

author: mzzj
author_rank: Super Contributor
timestamp: February 21, 2020, 10:15:46 am
content: Should be pretty obvious that untrained end-user has to never work with live circuitry.If you have accessible live parts inside the casing you need qualified electrician for the adjustments in most countries.In many countries this could also classify as "work with live circuitry" (EN 50110 standard?) and depending on situation it can be a total pain in the ass and real expensive.So worst-case you need qualified electrician to do the adjustments, shitload of internal corporation permits, red tape and safety reviews worth of 1 week.

author: poorchava
author_rank: Super Contributor
timestamp: February 21, 2020, 11:22:42 am
content: Vacuum forming is an option, but we'd like to avoid this at all if possible.What makes me wonder about all this, is that we've taken apart numerous products from competition, all of them of similar construction (no externla controls, have to unscrew the conver to mess with settings). Neither of them has any additional cover over live contacts, so they must have some common understanding of the standards. We haven't designed a product like this so far, everything up to that points had isolated and safe controls on the outside.They look more or less like this: (some random picture from google, but represents what i mean)https://au.rs-online.com/web/p/fan-speed-controllers/8841196/Those things (including our project) fall under either 60335 or 60730, which are mostly similar with respect to electrical safety (i can;t say for sure, I don't have full 60335 document). The instruction manual for the device linked above says:QuoteThis is very much the case of our device. In general it will be installed by trained technicians, who should know how to work when potentially live parts are accessible. I guess the norms expect everybody to call an electrician to ie. replace a light switch? (same situation - undo 2 screws, live wires are accessible).

author: mzzj
author_rank: Super Contributor
timestamp: February 21, 2020, 11:42:23 am
content: Quote from: poorchava on February 21, 2020, 11:22:42 amAFAIK most norms would require the electrician even if the wires are not live since its fixed installation. (and even then disconnected from suitable device, locked out and verified..)Handling actual live wires gets complicated surprisingly fast and the electricians look like this:Depending on jurisdiction and company.