Sunday, February 20, 2011

Field expediant connection danger


Recently I was working in a new customers Apartment building when they asked me to install a Receptacle switch combo unit were there was previously just a switch so that they could have a Receptacle in the bathroom. some times this can be accomplished when a neutral wire is available in the switch box but as in this case the switch was wired using what’s called a “dog leg” Just the hot wires for in and out on the switch were located in the switch box along with the ground wire . I told my customer it could not be done as there was no neutral wire in the box , but he insisted his other electrician “handyman” could make it work so he took me up to an empty apartment to show me how this so called electrician did this wiring trick . what I discovered was that the handyman took and put a wire from the Neutral terminal on the switch to the ground wire
in the box , not only is this a major violation of the national electrical code NEC
but it could lead to very serious consequences such as fire or electrocution.
1st a ground wire is never to be used for a neutral wire most ground wires are not heavy enough to properly carry a continuous return path of current they are there strictly to carry away accidental fault current
2nd when you use the ground wire or grounded metal electrical piping for neutral there can be serious voltage fluctuations in the circuit. as the ground wire could have many interconnected ground wires and metal surfaces attached to it. there by creating a high resistance in the circuit. and should there be an over load on the circuit ,the breaker or fuse may not clear the fault and this will result in fire. if the ground path should break
the person holding the metal part of the appliance they have plugged in would then become the ground path and receive a deadly shock.
After I explained this to my customer he had me go around and properly fix all the outlets illegally wired to the correct method , in which case since there was conduit run in the walls I was able to slide a neutral wire through the pipes up to the light fixture were I was able to obtain a proper neutral connection. for the receptacles
although you often see this violation in bathrooms you will also find it many times in residential garages were some one decides they want an outlet on the opposite side of the garage. they open up the box and find the plug does not work after wiring it in so a neighbor comes over to help and comes up with the ingenious way of making the outlet work by wiring the neutral wire to the boxes ground.
Over the years there have been many fires attributed to this type of wiring but all too often the evidence is destroyed due to the tremendous amount of heat electrical fires produce.
once gain if you are involved in fire investigations this is another area that needs to be checked when doing your investigation.

Note: I wrote and published this article in Pa. Fireman’s Magazine in 1998
Finally in the 2011 NEC code it is now required that there be a neutral wire or means available to get a wire to the location for all switches because they have finally realized the danger being posed by new energy saving switches that need neutrals and being attached to ground wires instead.

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