Brian Roth said:In the USA, I know that for AC power distro within a building (ie, the wiring to/from the breaker box to wall outlets, etc) requires a "solid neutral" per the National Electric Code. Further, Underwriters Laboratories definitely allows (requires??) only the "hot" leg to be switched within a piece of gear that receives the UL approval sticker.
Bri
Interesting! In France and Monaco, circuit breakers sense live only but must break both live and neutral.Brian Roth said:In the USA, I know that for AC power distro within a building (ie, the wiring to/from the breaker box to wall outlets, etc) requires a "solid neutral" per the National Electric Code.
Some other countries specifically request both poles to be switched, I think Korea is one.Further, Underwriters Laboratories definitely allows (requires??) only the "hot" leg to be switched within a piece of gear that receives the UL approval sticker.
Brian Roth said:Perhaps UL has changed their rules in recent times, but I've been inside a LOT of UL listed electronics gear that had only the hot lead switched, and the neutral "solid".
That's the way it's supposed to be, but electrical regulations are about what happens when something goes wrong.kepeb said:isn't the neutral hooked up to earth potential at source anyway?
You may like to measure the voltage between earth and neutral at your own house. If you want some fun, put an ammeter instead of voltmeter between earth & neutral. ;Dkepeb said:isn't the neutral hooked up to earth potential at source anyway?
ricardo said:You may like to measure the voltage between earth and neutral at your own house. If you want some fun, put an ammeter instead of voltmeter between earth & neutral. ;Dkepeb said:isn't the neutral hooked up to earth potential at source anyway?
OK. I shouldn't have said that. Don't try this at home. 8)
Harpo said:Switching both life/neutral is mandatory in wide parts of europe, FI Germany, Italy, Spain, Austria, Netherlands, .. that use the "Type F" CEE 7/4 Schuko plugs. Reason is, these plugs can be plugged into the wall outlet in either direction.
JohnRoberts said:There are also general rules for locating fuse wiring in the hot leg, so an open fuse will stop mains voltage at the fuse holder.
Kingston said:JohnRoberts said:There are also general rules for locating fuse wiring in the hot leg, so an open fuse will stop mains voltage at the fuse holder.
But again, quite impossible for the north European Schuko.
(somewhere on this forum maybe 5 years back lies my "doh!" moment discovery of this ambiguity. I was routing mains switch to front panel and it was causing some hum to the audio circuits. It occurred to me I should route only neutral to the front panel, and hum was gone. Some days later the hum was back when I had the mains cord plugged another way around. The working solution was of course good shielding for the wire and routing them both to the switch for safety.)
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