nuetral in swich boxes

[liquidtite]

im aware of the recent code change witch states that you must bring a nuetral to the switch boxes.I always thought this code applied to residential only, and I dont have 08 0r 11 nec on hand,but this rule came up in specs that im working on in a hospital. I was just woundering what is the pupose behind this code change?

 

[don_resqcapt19]

The rule 404.2(C) applies to light switch locations in all occupancies. The reason for the rule is the fact that the manufacturer's of electronic switching devices were using the EGC as a grounded conductor to power the electronics in their devices. This is (was) permitted by the product standard as long as the current on the EGC was 1/2mA or less per device. This current on the EGC is a shock hazard for someone working on the EGC. UL said that the standard would not be changed unless the NEC required the grounded conductor to be present at the light switch location.

 

[liquidtite]

gotcha thanks

 

[augie47]

There are exceptions that basically cover conditions where the neutral could easily be added later such as a conduit with sufficient area to add the wire. That's why some folks think it does not apply to non-residential locations.

 

[RustyShackleford]

There's a long thread here:

http://forums.mikeholt.com/showthread.php?t=150603&page=4&p=1458695&highlight=#post1458695

It appears that NC has eliminated the provision altogether for single-family residential. And apparently MA has made some common-sense modifications (e.g. not required if switch isn't in same space as light). I imagine other states have (or will soon have) followed.