Bonded Subpanel, Double Taps, and Aluminum Branch Wiring in a 1972 Split-Level
You inspect a 1972 split-level whose 200-amp main panel was replaced in 2016. Removing the deadfront, you find two 20-amp breakers with two conductors each under a single terminal screw, one feeding a bedroom and one a garage circuit. The panel cover was held on with four drywall screws. In the attached garage, a 60-amp subpanel has its neutral and ground bars joined by a green bonding screw, and the feeder is three-wire plus ground. Two bedrooms contain single-strand aluminum branch-circuit wiring at the receptacles, with purple wire nuts and anti-oxidant paste. The hall bathroom receptacle is a standard three-prong with no GFCI protection, and the label on it reads 'updated 2017.' The buyer is a first-time purchaser who plans to add a hot tub. Water heater is 2016 electric.
1. Rank the electrical findings by hazard and explain the failure mode behind each, so the buyer understands why they are in the summary.
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Sort by failure mode, not by how dramatic it looks.
- Subpanel neutral bonded to ground. In a subpanel fed by a 4-wire feeder, the neutral and equipment-grounding bars must be separated (NEC 250.24(A)(5), 250.32). With the green screw installed, normal neutral current returns on the feeder's grounding conductor and on every metal path between the two panels - conduit, enclosures, possibly water piping. That is objectionable current: a shock hazard at metal enclosures and a fire risk at loose connections. It is also the cheapest thing on the list to correct.
- Aluminum single-strand branch wiring. A 1972 house is squarely in the aluminum-branch era. The purple nuts and paste show someone has been at the terminations, which is better than nothing but does not make the circuit safe. Series arcing at loosened or backstabbed terminations is the mechanism. Write 'potential fire hazard, recommend evaluation by an electrician experienced with aluminum branch wiring' - not 'replace all the wiring,' which is a design decision.
- Double taps. Two conductors under one terminal on a breaker not listed for two conductors means clamping torque is shared and one conductor is likely loose. Overheating at the breaker is the result. Recommend correction by a licensed electrician.
- Bathroom receptacle without GFCI. A real shock hazard, but a conditional one - it injures when a person is grounded and the appliance faults.
All four belong in the safety summary. The first three justify 'evaluate before occupancy' if the buyer asks about urgency.
2. Why do you write 'recommend evaluation by a licensed electrician' instead of specifying the repair, and what should the report disclose about the limits of the electrical inspection?
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Because I am not licensed to design the fix, and the fix depends on facts I did not establish. A double tap might be resolved with a pigtail, a two-pole breaker, or a breaker listed for two conductors - the choice depends on conductor size, load, and the panel's listing, none of which I verify. If I write 'install a GFCI breaker' on a circuit that turns out to be a multiwire branch circuit, I have created a hazard and taken on the liability for it.
Disclose the scope honestly. The SOP has me remove the panel cover where it is safe and inspect what is visible. It does not have me de-energize, torque terminals, trace every circuit, open every device box, or calculate loads. The report should say so: 'Panel interior was inspected with the deadfront removed. Circuit tracing, conductor ampacity verification, and load calculations were not performed. Drywall screws were used to secure the panel cover; the cover should be secured with the manufacturer's fasteners.'
The wording pattern: observation, consequence, referral. 'Two 20-amp breakers have two conductors under a single terminal. Breakers of this type are not listed for two conductors, and the connection can overheat. Recommend a licensed electrician evaluate and correct.' That sentence holds up whether the electrician finds a serious problem or a code-compliant installation with a permitted exception.
3. The buyer mentions they want a hot tub. What do you tell them, and what do you deliberately not tell them?
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What the buyer is really asking is not 'is my panel big enough' but 'what will this cost and will it be done right.' My job is to flag constraints and stay out of the design business.
Facts worth giving them. A hot tub needs a dedicated circuit with GFCI protection, an emergency shutoff within sight but not less than 5 ft from the water's edge, and equipotential bonding of metallic parts. If it is fed from a subpanel, the feeder is 4-wire. Whether the existing 200-amp service can carry the added load is a load-calculation question under NEC Article 220 - that is an electrician's calculation, not a visual inspection finding. Two local issues bear on it: the garage subpanel's bonded neutral has to be corrected before anything is extended from it, and the double-tapped breakers mean the panel is already out of slots done properly.
Report wording. 'The buyer intends to install a hot tub. Service capacity and circuit design for that addition were not evaluated as part of this inspection. Recommend a licensed electrician perform a load calculation, obtain a permit, and install the circuit per NEC Article 680; the work should be inspected by the local authority.'
What I deliberately do not do: size the conductors, name a breaker, or say 'your panel will handle it.' Those are the sentences that get quoted back when the tub trips the main on a cold night.