Re: Rehabbing, but rewiring? - Posted by Jim Locker
Posted by Jim Locker on June 26, 2001 at 22:22:45:
You would certainly have to be careful to avoid crossing a hot and a neutral if you wire the ground to the neutral at the outlet. This type of miswiring would be quite hazardous.
Assuming you wire it correctly, the possible malfunctions to the house wiring basically consist of one possibility: a connection comes loose through corrosion or other influence (such as a mouse chewing).
If the connection that comes loose is the hot side, then the outlet goes dead. You then track it down and fix it.
If the connection that comes loose is the neutral side, then the outlet may or may not go dead; if any kind of circuit to ground can be found anywhere, then the outlet may still appear to work, but you have a very dangerous condition which could lead to electrocution or a fire.
Typically, in a three wire system, if the neutral goes down then the ground wire is available to carry the current, which greatly reduces the hazard. If a GFCI is connected on the circuit that loses the neutral, the GFCI will detect the current flowing on the ground wire and will trip.
Under the conditions where you wire neutral and ground together at the outlet in order to simulate a 3 wire system, you do not have the protection against the failed neutral wire but you maintain all the other advantages of the three wire system.
Really, failures in wiring inside walls are quite rare. Typically, you will encounter this if you have aluminum wiring in the house (all of that is probably gone by now), or if you have a house in very poor condition.
Wire failures can occur if connections continually get wet (such as due to roof or plumbing leaks that are not attended to), if there is a serious rodent problem in the house (the critters will get bit if they chew on the hot side, but they can chew on the neutral side without harm…until the wire parts), or if the house is deteriorating structurally (walls sagging, floor sagging, things move and pinch or pull wires).
If none of these pathologies applies to your house, then you have no particular issues to watch for when wiring the ground and neutral together at the outlet.