2 grounding/bonding questions

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JWelectric

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The equipment grounding conductor was not a requirement until the 1962 cycle of the NEC so a house built in the 40s wouldn’t have known about the EGC.
The purpose of the armor was protection of the conductors not a fault current path for the more modern magnetic trip circuit breakers.

During the first half century of the electrical history circuits were protected from overload only. The most common form of protection was the Edison base fuse. Most receptacles were of the two wire configuration.

Through the evaluation of the NEC circuits continually get safer. One of the first moves was the induction of the equipment grounding conductor that serves as a fault clearing conductor.
The first circuits that required this new technology was the washing machine. The first circuits in residential systems that required an EGC were cloths-washing, cloths drying, and dish washing machines, see 250-45(c) of the 1962 Edition of the NEC.

My first year in the trade was in 1966 and even though it had been four years it was still the biggest thing being talked about around the old Warm Morning cold stove in the supply house. The talk about the requirement for installing the EGC and the need to file bankruptcy died away in 1968 with the first requirement for GFCI for a pool light. The requirement for GFCI protection held everyone’s attention for many years mostly because 0f the requirements that were continuing every code cycle until the arc fault requirement. Yes I can remember as much talk about the introduction of the EGC as we are hearing about arc fault today.

The metal armor of the raceway in houses built in the 1940s in no way was intended as an EGC.
 

Cacher_Chick

Test, Don't Guess!
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The NEC did not require a separate ground conductor until some time around 1962, so any home built prior to that would not be expected to comply. When is comes time to retrofit, it would commonly be time for a re-wire anyway.

Most of those old houses did not have an adequate number of well-placed receptacles to be very functional in today's world.
 
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The equipment grounding conductor was not a requirement until the 1962 cycle of the NEC so a house built in the 40s wouldn’t have known about the EGC.

The metal armor of the raceway in houses built in the 1940s in no way was intended as an EGC.

Ah. Yes. Before '62 there was no requirement for an EGC. And the metal conduit was not meant as an EGC, but rather as part of a wiring structure; it provides a path and physical protection for the conductors that are fished into it.

After '62 we need a green grounding wire to bond all the equipment.
 
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