low voltage wiring

Are there any regulations concerning EMI and noise with low voltage wiring? Where can I find information on this?

Thanks,

The IEC may have some guidelines. In general, keep your low voltage wiring in separate wire ducts and conduit from AC power and control wiring. For analog signals use shielded twisted pairs, and ground the shield at one end of the wiring only. Inside the panel keep the AC and DC wiring in separate wire ducts, and keep control transformers etc. away from analog devices as much as possible.

thanks tom, this is really a post for my students to see, to force them tocome to this site. I know the answer, but want them to look it up. Thanks again for the post, perhaps it will give them some ideas.

Answer

THANKS TO TOM THAT GEVE AS THE ANSWER, AND THANK YUO FOR GAVE AS THIS PAGE

HUH? Thats not much of an answer, answer the question.

Shawn, I think that particular student needs a refresher course in spelling and grammar before you start discussing electrical stuff! banghead

beerchug

-Eric

emi regulations

Tom's answer seems pretty complete. In addition to IEC (in particular the 801 series) FCC speaks to the EMI problem (part 15) but not so far as it relates to PLC's, mostly communication type stuff. One additional thought is where ever possible, select current driven devices (i.e. 4-20ma) over voltage type (1-5vdc, 0-10 etc.) as they are less susceptible to noise. Also banning Rap, Hip Hop, and club music from 500 to 1000 feet of the PLC might also help eliminate noise from the area.

well, at least one of my students gave an appropriate answer. For the rest of them---its on to the rack!

The revised Low voltage Directive (73/23/EEC plus parts of 93/68/EEC) became mandatory on 1st January 1997. As of that date, all electrical and electronics products entering the European Community (EC) countries must comply with the electrical and safety requirements of the revised Low Voltage Directive (LVD).

This seems to be more of a Europen standard. This informtion was attained from the EMC Tech site. There is informaion on the FCC.GOV site but it is difficult to find. Search for LVD / EMC / EMI.

There was some other info on the web that I came accross but it to seemed to deal more with European contries.

Dan J
PLC Class

Low Voltage Wiring EMI

I found EMI for low voltage wiring of control systems at:

www.yorkland.net/emiisue.htm