First off I am NOT recommending that people remove the electrical
ground connection, BUT this is not a totally black and white situation.
For instance in many high end audio recording studios, all the electrical grounds are removed from devices in the Racks, and what is implimented is a STAR
ground configurion, where a
ground connection is made to the chassis and the rack from all the devices and THEN that
ground is connected to the electrical
ground. So the devices do not really have the
ground removed, BUT they are not using the grounding connectiion in all the individual electrical wiring for a
ground connection. I have seen this also used in some location audio setups, where an independant
ground system is used, and that this is then connected to the electrical
ground.
Problem is there are a lot more problems than simply someone removing the third pin on electrical cords. I have found many many times where the actual outllet was wired incorrectly with the Hot and
neutral connection reversed, where the
ground is NOT connected, or where the
ground is connected to the
outlet case, and
conduit, only to have the
conduit connections coroded or broken along the way. I have found
ground and
neutral connections reversed. There is an issue that a lot of consumer equip does not have a
ground connection instead relying on the double insulated
rating of the device. I have found that it is these types of devices that many times are the sources of the
ground noise. Pc's with switching
power supplies tend to
return quite a
bit of noise on the
neutral, and in a poorly constructed
ground system this can cause problems. I have also found panel boxes that have a
neutral bar and a
ground bar, and have a place to use a
bolt to connect the
neutral to the case that this has been incorrectly used when there should only be the one connection of
Neutral to
Ground at the Service entrance.
I agree extension cords that have the
ground pin removed should not be used, but for instance it could be argued if the device connected to them is a two pin connection then it IN this specific use is not a
safety issue.
A oot of the problem goes back to how things were wired up in the past, the unwillingness of code regulations to impliment something that MUST be changed. There are may old buildings that do NOT have
ground connections on outlets, but to make it look like they do have three pin recepticals that are only partially or not connected to electrical
ground. Even in areas outside of the US there are still are devices that do not use three
wire setup, as mentioned aloo at all the wall warts, notebooks, electrical lights, and many consumer devices even TV's.
There are a lot of oddities in code implimentations that cause potential problems. I can give you some examples:
In the US on 20 amp wall sockets, there is no requirement to have one
breaker for one
outlet, so in theory you can have many many wall sockets on a 20 amp connection over 12
awg wire, with additional outlets added over time. Will an over
current situation pop the
breaker, probably but there is STILL the possibility of overheating. Many homes have burned ot the
ground based on two many heaters put on the same series of outlets.
In marine setups, many of the marina;s use a three
phase setup for connection to the dock and then
break out 120 and 208 connections, Problem is the
power cords do not have double rated neutrals, and if you ask boaters who use shore
power alot, you will get endless tales of burned connectors based on over load on the
neutral and the damp environment.
Back to theatrical and event production, it is because of all the unknowns iin the facility wiring that so many companies now bring their own
distro and cableing, and get it wired in to a
company switch or back to the main
breaker panel.
Again extension cords with
ground pin removed are bad and dangerous, but at least YOU CAN SEE THE PROBLEM. The conditions that can really get you hurt are the ones hidden in the walls and connections.
Sharyn