Material · 600 V building wire
We buy THHN and THWN wire in Houston.
The most common leftover in the city: spools and partial reels of 600 V thermoplastic wire that came off a commercial job and never went back to the distributor.
THHN is the default building wire in Houston. It runs in conduit on commercial jobs, in gutters and panels, in machine rooms and in the back of every electrician's van. Because it is bought in standard spools and reels, the leftover is almost never zero.
That leftover is what we buy: full spools still banded, opened spools with most of the length left, partial reels of larger sizes, and the mixed pile of short coils that accumulates at the end of a project.
What THHN and THWN actually are
THHN, THWN and THWN-2 are 600 V thermoplastic-insulated wires with a nylon jacket over the insulation. The designations describe the ratings: heat resistance, moisture resistance and, in THWN-2, both at the higher temperature. In practice the same spool is usually dual or triple rated and marked for all three.
It comes in copper and aluminium, from 14 AWG branch wire up to 500 MCM and larger feeders, in a long list of colours and stripe combinations. Sizes above 4 AWG are usually stranded; smaller sizes may be solid or stranded.
- 14, 12 and 10 AWG branch circuit wire
- 8 and 6 AWG for small feeders and subpanels
- 4 AWG to 500 MCM for feeders and services
- Copper, and aluminium in the larger feeder sizes
- Black, red, blue, white, green and every stripe in between
Where Houston leftovers come from
Commercial construction is the main source. A tenant improvement in the Galleria, a school addition in Katy, a warehouse fit-out in Pearland: each one orders wire by the spool, uses most of it, and leaves the balance on a shelf in the trailer. When the job closes, nobody wants to pay to move it.
Contractors with several crews generate a steady trickle from service work, and electrical distributors contribute overstock when a size or colour stops moving. Industrial plants keep THHN for maintenance and often hold obsolete colours and sizes for years.
What decides whether a THHN lot is worth collecting
Size and metal come first. A partial reel of 500 MCM copper is a different proposition from three coils of 14 AWG. Beyond that, the questions are simple: is the wire clean and dry, is the jacket intact, is it still on a spool that can be handled, and is the length meaningful.
Colour matters less than people expect. Standard colours move; odd stripes and obsolete shades do not, and they are valued accordingly. Aluminium THHN in larger feeder sizes is bought, but at a different basis to copper.
- Conductor size and material
- Remaining length, and whether it is continuous
- Jacket and insulation condition — no water, no UV damage
- Whether the wire is still on a spool or in a loose coil
Wire that has been pulled through conduit and removed is a different grade from wire that never left the spool. Say which it is.
Why spools go bad in a Houston shop
Wire is durable, but a spool left against a roll-up door for two summers is not the same product. Ultraviolet light attacks the jacket, heat softens it, and a roof leak puts water into the coil where it sits against the copper.
The damage is usually at the outside layer and the cut end. A spool that has been stored indoors, off the floor, with the end taped, is easy to review. One that has been outside since the job closed is reviewed on the visible jacket and priced with the risk included.
- Indoor storage, off the concrete, end taped
- Outside under a tarp that traps condensation
- Spool crushed or flange broken in handling
- Wire pulled through conduit and returned to the spool
How to send a THHN lot
List the sizes, the approximate length on each, the colour if it matters, and whether it is new or pulled. A photograph of the spool tag and one of the wire end is enough for an initial review.
For a mixed pile, photograph it as a group and give a rough count by size. Sorting is part of the review, and a mixed lot does not need to be separated before it is offered.
The sizes that actually matter
Demand is not spread evenly across the size range. Branch-circuit sizes move constantly because every job uses them, while a 500 MCM feeder spool is a slower item that is bought on its copper content as much as its usefulness.
In practice that means a pallet of mixed 12 and 10 AWG is a volume lot, and a single partial of 350 or 500 MCM is a value lot, even though the second is a fraction of the weight. Colour follows the same logic: standard black, red, blue, white and green move; striped and obsolete shades are priced as mixed.
If a lot spans both, say so. The two halves are reviewed on different terms, and a single combined description usually undersells the larger sizes.
Related review paths
Questions sellers ask
Do you buy opened spools with only part of the wire left?
Yes, as long as the remainder is meaningful and the wire is clean. A spool with 400 feet of 12 AWG left is a normal lot; a spool with 30 feet is usually grouped with other material rather than collected on its own.
Is aluminium THHN bought the same way as copper?
No. Aluminium is lighter and lower value per pound, and it is judged more strictly on condition at the ends. It is still bought, particularly in 4 AWG to 500 MCM feeder sizes.
Does the colour affect what a lot is worth?
Sometimes. Black, red, blue, white and green move; odd stripes and discontinued shades sit. A mixed-colour lot is normal and is priced as a package rather than by colour.
Can I include THHN with other cable in one lot?
Yes. Mixed lots are common from contractors and warehouses. Group the material by type on the pallet where you can, and photograph each group so the review does not stall on sorting questions.
Buying desk · Greater Houston
Got this cable in stock?
Tell us what is on the reel, where it sits and what condition it is in. A buyer reviews the lot, asks for photographs of the tag and the cut end, and comes back with a real answer — not a request to call a call centre.
- Cable type, size and voltage class
- Footage, reel count or weight, and condition
- City, and whether the site has loading equipment