Receptacle Replacement and Extension on Ungrounded 1950s Wiring
A 1955 dwelling has 2-wire, no-ground NM cable throughout. The kitchen has three existing receptacles on one 20 A circuit, about 4 ft from the sink; two are cracked and one is a 15 A, non-tamper-resistant type. The dining room has one receptacle. The owner wants all the receptacles replaced, a new receptacle added for a microwave in the dining room, and a new receptacle under the kitchen sink for a disposer. The electrician proposes to 'just put in regular three-prong receptacles and jumper the neutral to the green screw like the old guy did in the bathroom.'
1. How must the kitchen and dining receptacles be replaced on a circuit with no equipment grounding conductor?
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Jumpering neutral to the grounding screw is prohibited - 250.24(A)(5) and 406.4(D) forbid using the grounded conductor as an equipment ground downstream of the service. It creates a shock hazard and is a classic false 'fix.'
Compliant options for replacing receptacles on an ungrounded circuit (406.4(D)(2)):
- Install a GFCI receptacle at the first outlet of the circuit, or a GFCI circuit breaker, and protect the downstream receptacles.
- Protect with a GFCI and mark each downstream receptacle 'GFCI Protected' and 'No Equipment Ground' (406.4(D)(2)(b)-(c)). The marking must be on the receptacle or cover plate.
- Run a new equipment grounding conductor to the receptacle per 250.130(C) - it may be run to any accessible point of the grounding electrode system, the grounding terminal of the service, or a grounded receptacle upstream on a grounded circuit.
Tamper-resistant: 406.12 requires listed TR receptacles in dwelling units, so 'like-for-like' 15 A non-TR units cannot go back in.
Kitchen GFCI: 210.8(A) requires GFCI protection for all 125 V, 15/20 A receptacles serving kitchen countertops, and the 4 ft to the sink makes that certain. So the kitchen receptacles need GFCI protection regardless of the grounding question.
2. What is required to add the new dining-room microwave receptacle and the disposer receptacle under the sink?
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Extension of an ungrounded circuit (dining room): this is not a 'replacement' under 406.4(D). Extending a circuit is a new installation, so the receptacle must have a proper equipment grounding conductor (250.130(C)) - either run an EGC back to an acceptable point in the grounding system or run a new grounded circuit. A GFCI-only approach is defensible only where the AHJ treats it as a replacement; as a new outlet the EGC is required. Practically: run a new 12/2 with ground from the panel or from a grounded junction, place the microwave on a dedicated 20 A circuit, and add AFCI protection per 210.12 for the dwelling-unit branch circuit.
Disposer under the sink: 210.8(A) treats the area near the sink as requiring GFCI; a receptacle within 6 ft of the outside edge of the sink must be GFCI protected. Use a GFCI receptacle or GFCI breaker, a proper EGC, and a metal-clad or nonmetallic box with a cord-and-plug or direct connection as allowed. The old 2-wire cable cannot be reused to feed this new outlet.
Both new outlets require the correct box fill and device grounding per 314.16 and 404.9(B); the yoke must be grounded, which is not possible without an EGC.
3. The owner asks whether the existing 2-wire cable can stay for the replaced receptacles and whether the panel breaker needs to change. What do you tell them?
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Existing cable can stay for the replacement-only receptacles. The code does not require rewiring the house to replace receptacles; it requires the replacement to be made safe - GFCI protection plus the 'No Equipment Ground' marking, or a new EGC. What cannot happen is a three-prong receptacle with an open ground and no marking, or a bootleg neutral-ground jumper.
Breaker: a GFCI circuit breaker in the panel is an accepted way to provide the protection (406.4(D)(2)(a)(1)) and also protects the downstream devices. If a GFCI receptacle is used instead, the first outlet must be identified and the downstream receptacles marked. Note that shared neutrals (multiwire circuits) will trip a single-pole GFCI breaker - check the circuit arrangement before choosing.
Also verify: the 20 A circuit must actually be 12 AWG; a 20 A breaker on old 14 AWG is a fire hazard. Check the panel for double-tapped breakers and undersized service conductors while the cover is off. Document the 'No Equipment Ground' markings and the GFCI test in the job file so the next electrician and the inspector can see what was done and why.