Weekly digest #34: price changes in copper

Copper is moving again

Spot copper pushed through $4.80/lb this week on the COMEX, with bare #2 scrap in most yards paying between $3.60 and $3.90. Distributor counter prices on THHN and MC followed within 48 hours. If you quoted a panel swap or a service upgrade two weeks ago and haven't ordered wire yet, your margin is already bleeding.

The driver is the usual mix: grid buildout, data center transformer orders, and tight mine supply out of Chile. None of that reverses quickly. Plan bids with the assumption that wire goes up again before it comes down.

What actually changed on the shelf

Pricing moves you'll see this week at the supply house, based on averages from three Midwest distributors and two national chains:

• #12 THHN stranded, 500 ft spool: up roughly 7 to 9 percent.
• #6 THHN, per foot cut: up about 6 percent, with some branches out of stock on black.
• 4/0 SER aluminum: flat to slightly down, which matters for your service feeders.
• 12/2 and 14/2 NM-B, 250 ft: up 4 to 5 percent.
• 3/0 copper XHHW-2: up nearly 10 percent, longest lead times of the group.

MC cable pricing lagged the raw commodity by a few days but is catching up now. If you run a lot of 12/2 MC on commercial tenant work, lock in a pull quantity this week rather than buying reel by reel.

Specing aluminum where code allows

When copper spikes, the aluminum question comes back. For service entrance conductors and feeders, AA-8000 series aluminum is code compliant under NEC 310.14(A) and sized per 310.16. A 200 A dwelling service runs fine on 4/0 aluminum SER per 310.12, which is the table most inspectors will check first.

Branch circuits are a different story. NEC 110.14 still governs termination compatibility, and most 15 and 20 A devices are CU only. Don't land aluminum on a standard receptacle and don't mix conductor materials at a splice without a listed connector rated for both.

Tip from a service tech in Ohio: when you switch a feeder from copper to aluminum mid-job, re-check the EGC size against Table 250.122. The equipment ground does not scale the same way as the ungrounded conductors, and inspectors catch this one constantly.

Voltage drop math gets tighter

Aluminum has roughly 61 percent the conductivity of copper, so a substitution usually means going up one or two sizes. On longer runs, that eats into the savings fast. Run the numbers before you commit.

Quick reference for a 120 V, 20 A branch circuit at 80 percent load, targeting 3 percent drop per the informational note in NEC 210.19(A):

1. #12 CU: good to about 60 ft one way.
2. #10 CU: good to about 95 ft one way.
3. #10 AL: good to about 60 ft one way, same as #12 copper.
4. #8 AL: good to about 95 ft, and still cheaper than #10 copper on most days.

For feeders, NEC 215.2(A)(1) sets the 3 percent guidance, and the combined branch plus feeder target is 5 percent. On a 150 ft run to a detached garage subpanel, aluminum almost always wins on material cost even after upsizing, but verify your lug ratings on both ends.

Bid protection when material is volatile

Fixed-price bids written more than 10 days out are exposing you to commodity risk you are not being paid to carry. Two practical moves:

• Add a material escalation clause tied to a published index. COMEX copper settlement plus a stated percent for jacket, insulation, and handling works and is defensible in a dispute.
• Break out wire as a separate line item with a 7 day price validity. Customers push back less when they can see the commodity is the variable, not your labor.

On service change work where the wire is a small fraction of the total, just pad. On larger commercial pulls, get it in writing.

Tip from a shop owner in Texas: when copper moves more than 5 percent in a week, we pull every open bid over $10k and re-issue with a new date. Takes an hour and has saved us four figures per quarter.

Theft risk climbs with the price

Every copper run since 2021 has brought a bump in site theft. Empty new construction, unsecured gang boxes, and spools left overnight in open trailers are the obvious targets. Grounding conductors on rooftop HVAC and service laterals at commercial sites are the less obvious ones.

If you are responsible for site security language in your contract, tighten it now. If you are the one leaving material on site, do not. The insurance deductible on a $3,000 spool theft is usually higher than the spool.

Track scrap value against job cost too. A lot of shops are still paying apprentices to toss cutoffs. At current prices, a five gallon bucket of #12 stripped copper scrap is worth real money at the yard.