Is a 2 conductor circuit "ungrounded"?

How do you refer to the pre-1962 circuits in your reports. The older 2 conductor types. Do you refer to that wiring as “ungrounded”?

If it is all including panel is from 1962 .
I would write .
Electric system was adequate for the Sixties .
I recommend you check with your Insurance company re Coverage .
With today’s requirements I recommended a complete upgraded immediately .

I am 62 years old and have been in the trade almost 45 years but I have never seen an ungrounded residential electrical system in my entire life.

I have seen many residential electrical systems that did not have an equipment grounding system.

I have also worked on many ungrounded systems but in most cases they were supplied by a Delta 480 volt system in some industrial plant.

There is a huge difference between a system that does not have equipment grounding conductors in the branch circuits and an ungrounded system.

Ungrounded. Not connected to ground or to a conductive body that extends the ground connection.
Ground. The earth.

Any system that has 120 volts will be a grounded system as the neutral will always be connected to earth by the utility company at the transformer that supplies the service. The neutral is grounded therefore if the system has a neutral then it is a grounded system.

On two wire systems I report them as having no equipment grounding conductor. I do not report them as being ungrounded systems.

You win a GOLD STAR!

Joe thanks for this thread and thank you Mr. Whitt for that awesome explanation

The neutral is actually called the “grounded conductor”.

Posted in: Outlets
Ungrounded Electrical Receptacles
By John Chavez
Jun 25, 2007 - 9:58:53 AM

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**Ungrounded Electrical receptacles **
**Q: **The property inspector listed within his report that there were ungrounded electrical receptacles throughout the house. What is the difference between the ungrounded electrical receptacles being “throughout” the house and one or two ungrounded electrical receptacles? And, what can be done to correct this?
**A: **There are typically two situations where ungrounded electrical receptacles will be present. The first is the sporadic presence of an ungrounded receptacle or circuit in a fully grounded system as a result of a loose grounding wire for one receptacle. If the receptacle that has a loose ground is the first in a circuit, the remaining electrical receptacles of the circuit will also be ungrounded.

The second instance is when the complete electrical branch system of the house is ungrounded. This is common in most homes built prior to 1970 that had only a two wire ungrounded system and in homes pre 1960 where a knob-and-tube independent wire circuitry with no ground was used.

If the inspector described the presence of ungrounded electrical receptacles throughout the house in the report, it is very likely that the complete electrical system is ungrounded and three prong electrical receptacles have been installed at several locations. Another common trait of ungrounded systems is that the original electrical receptacles installed in this type of system were two prong electrical receptacles and in most cases, some of these two prong electrical receptacles will still be present behind furniture or inaccessible areas of the house.

I’d say: call the wire type and the equipment grounding separately.

  1. “Building contains Knob & Tube electrical wiring, a style typical for the era of construction…”
  2. “Outlets in the house are two prong, without an equipment ground…”

If there are any pretend 3-prong outlets call that separately and more urgently.
3-prong GFCI outlets without ground are OK: new ones come with a sticker for use in exactly this situation (it reads ‘no equipment ground’).

Some insurance companies won’t write a policy on a house that has K&T wiring, others require a certification first.

In California and Oregon we like our K&T, and both states have more K&T friendly policies and insurers. Prior to insulating for example there’s a procedure to inspect the K&T for bootleg extensions and proper ampacity (the K&T itself is very robust against degradation). An electrician is qualified to improve on things: install an AFCI breaker on K&T, and possibly drop one breaker size (e.g. 15 amp AFCI if the wire is 12 gauge)…

No. Residential electrical systems are, as Mike Whitt said, all grounded and always have been.

A 1963 build house I inspected a couple of days ago actually had 2 conductor types receptacles replaced in some areas.

In my report, it read:

· Safety Issue:** Older ungrounded outlets have been replaced with modern **three-slot grounded-type outlets in some areas; however, it appears the original wiring serving the outlets was not upgraded to grounded wiring. This represents a safety hazard since grounded appliances with three-prong plugs can be plugged into the ungrounded outlet, risking possible shock should the appliance malfunction. In some cases, grounded appliances can be damaged if plugged into an ungrounded outlet. A grounded circuit should be provided for all three-slot outlets.
You should engage a qualified electrician **to discuss the best course of action for upgrading to grounded outlets. Repairs should be undertaken as deemed necessary by the electrician. **In the meantime, do not plug three-prong cords into the outlet.


Just curious as to what any of you would report for an early 1960’s house wired with AC cable where the two prong receptacles have been changed to three prong. Many of the 1960’s and 70’s homes around here were wired in AC cable.

I wouldn’t report anything as this has been an acceptable EGC. Now, it will now require an individual EGC besides the internal bonding strip or shunt wire for the ac cable.


very nice verbiage Mr. Whitt.
Thank you.

Type AC cable uses the sheath in conjunction with the bond strip as an EGC. There is no need for anything else.

Type MC has an EGC inside the sheath and does not use the sheath as an EGC.

As Robert pointed out it is possible for the wiring method to only have two conductors and still be grounded and would allow three prong receptacles.

I’m asking because I see this often (two prong receptacles replaced with three prong and AC cable) and find varying incorrect things mentioned in the inspection reports.

I’m not sure that I agree with the statement in your last sentence.

Its my understanding that ac cable on it’s own without an additional EGC is no longer accepted by the NEC as an approved EGC. Is this correct?


Nope, with type AC cable it’s still acceptable to use the metallic outer sheath as an EGC.

Thanks Robert. I thought I read somewhere that had changed. Better start checking the code book more often. Appreciate it.


Take a look at 2011 NEC, 250.118.