SPEC300 kcmil at a glance
| Also called | 300 MCM |
|---|---|
| Conductor area | 300 kcmil · 152 mm² |
| Stranded (Class B) | 37 strands · 0.63 in |
| THHN outside diameter | ≈ 0.766 in |
| Finished copper wire weight | ≈ 1,030 lb / 1,000 ft |
| Bare copper weight | ≈ 927 lb / 1,000 ft |
| Common put-ups | 1,000 ft reels · 2,500 ft reels |
| Conductor | 60 °C | 75 °C | 90 °C |
|---|---|---|---|
| Copper | 240 A | 285 A | 320 A |
| Aluminum | 195 A | 230 A | 260 A |
Dimensions from NEC Chapter 9 Tables 5 and 8. Weights are approximate and vary by manufacturer and insulation. For design, follow the NEC and a licensed electrician.
Wire types we buy in 300 kcmil
01How to Identify 300 kcmil or 300 MCM Wire
Start with the jacket print and reel tag. Look for the conductor size, copper or aluminum identification, insulation designation, manufacturer and date code. Clear photos of those markings help us separate reusable surplus 300 kcmil cable from material that needs closer inspection.
300 MCM is another name for 300 kcmil; both describe conductor area. It is not an aught designation, and it should not be identified by comparing it with an aught-size cable at a glance. Our wire gauge chart explains the AWG and kcmil naming systems.
The supplied Class B stranded construction has 37 strands and an approximate conductor diameter of 0.63 inch. Approximate THHN outside diameter is 0.766 inch, including insulation and jacket. Those dimensions are identification aids, not substitutes for markings: construction and insulation affect the finished diameter. Photograph exposed conductor ends if available, but do not strip otherwise usable wire just to identify it.
02What the 300 kcmil Specifications Mean
The conductor area is 300 kcmil, approximately 152 mm². That describes metal cross-sectional area, not the cable’s overall diameter. Copper and aluminum conductors of this size have different weights and ampacities, so the metal must be identified before evaluating either installation suitability or resale value.
Under NEC 310.16 at 30°C ambient, before adjustments, copper ampacities are 240 amps in the 60°C column, 285 amps in the 75°C column and 320 amps in the 90°C column. Aluminum values are 195, 230 and 260 amps in those respective columns. See our wire ampacity chart for the table context.
These are reference values, not a blanket approval for a particular feeder. Terminal temperature ratings, installation conditions and applicable adjustment or correction requirements determine which values can be used. A 90°C insulation marking does not automatically permit loading to the 90°C table value. Have a licensed electrician or engineer confirm the design and installation requirements.
03Common Uses in Houston Construction and Plants
300 kcmil conductors appear in larger feeder work across Houston construction and industrial projects. Common applications include copper feeders using the 285-amp reference value, aluminum feeders for 225-amp loads, parallel sets in switchgear and generator feeders. Each application still requires a design check; conductor size alone does not establish a complete circuit rating.
Surplus can remain when a feeder route changes, equipment locations move or purchased reel footage exceeds the installed run. For sellers handling construction closeouts or plant inventory, intact reel tags and separate storage by metal and wire type make the remaining material easier to evaluate.
Keep parallel-set leftovers identified by conductor and remaining length rather than grouping everything under a single weight. Matching lengths and clear markings help us assess potential reuse. For generator or switchgear leftovers, tell us whether you are offering individual insulated conductors or a cable assembly. We review the actual material, not just the equipment application it originally served.
04300 kcmil Wire Types We Buy
We buy new, unused and reusable 300 kcmil THHN/THWN-2 wire and XHHW-2 wire, in copper or aluminum. Read the actual jacket designation rather than assuming the type from its color or appearance. Send photos showing the complete print where possible, along with the reel label.
Full reels are straightforward to document, but partial reels, coils and usable cut lengths also deserve review. Describe whether the wire remains on its original reel, has been rewound or is stored loose. Tell us about jacket damage, exposed ends or missing labels before scheduling a material visit.
We focus on material that can be reused. Short pieces, burned insulation and heavily damaged wire may be better suited to scrap rather than resale as usable cable. A cut length is not automatically scrap; usable length, identification and condition matter together. We will tell you what appears reusable and base the written offer on the material reviewed.
05How Footage, Weight and Packaging Affect Value
300 kcmil copper wire value depends on more than the copper market. Wire type, current demand, footage, manufacturer, date code, quantity, reel condition and pickup logistics all affect the offer. Reusable wire is usually worth more than its scrap, or melt, value.
Common put-ups include 1,000-foot and 2,500-foot reels. For finished copper THHN/THWN-2, approximately 1,030 pounds of wire corresponds to 1,000 feet. As a simple estimate, a net wire weight of 1,030 pounds divided by 1,030 pounds per 1,000 feet gives approximately 1,000 feet. Exclude the reel and packaging weight; gross reel weight is not net conductor weight.
Bare stranded copper is approximately 927 pounds per 1,000 feet, while bare aluminum is approximately 282 pounds per 1,000 feet. Do not use those bare-metal figures to estimate finished insulated cable footage. Our copper wire weight chart provides reference context. When you sell wire reels, send tag footage and net weight if both are available.
06Selling 300 kcmil Wire in Houston
To request an offer, text 951-403-5738 or email industrial832@gmail.com with tag and jacket photos, footage or weight, and the material’s location. Our process is review, written offer, scheduled pickup or drop-off, on-site verification and payment per the written offer. Use the offer request page to organize the details.
We serve Greater Houston only: Harris, Fort Bend, Montgomery, Brazoria, Galveston, Chambers and Waller counties. Wire pickup in Houston is scheduled at the seller’s site. For heavy reels, describe site access, reel condition and available loading arrangements so handling can be discussed before scheduling.
Drop-off is by appointment only at 6402 McGrew St, Houston, TX 77087. The address is in southeast Houston’s Mayfair area, near I-45 and I-610. Call first rather than arriving with a loaded truck. If footage or condition differs from the submitted information, we verify the material on site before payment under the written offer.
FAQQuestions sellers ask
Should I strip reusable 300 kcmil copper wire before selling it?
Contact us before stripping it. Removing sound insulation changes the material from an identifiable insulated conductor into bare metal and can remove information useful for resale. Keep the jacket print and reel tags intact, photograph the wire as stored, and let us review whether it has value as reusable cable.
Can you review a mixed lot containing 300 kcmil copper and aluminum?
Yes. Identify the copper and aluminum portions separately and provide footage or weight for each where available. Include photos of each wire type and its markings. A single combined weight does not show how much of each metal or insulation type is present, which limits how accurately we can evaluate the lot.
Does an older date code automatically make 300 MCM wire scrap?
No. Manufacturer and date code are factors in our review, but age alone does not describe the wire’s condition or current demand. Tell us how the material has been stored and show its jacket, ends and packaging. We assess identification and reusable condition rather than treating every older reel as scrap.
What if the reel tag and my estimated remaining footage disagree?
Send both figures and explain how you estimated the remaining length. A reel tag may describe the original put-up rather than what remains after cuts. Do not present original tag footage as confirmed remaining footage. We review the information you provide and verify the material on site as part of the sale process.
Are Houston Wire Buyers and Houston Wire & Cable Company affiliated?
No. Houston Wire Buyers is not affiliated with Houston Wire & Cable Company or any manufacturer. For a surplus 300 kcmil wire offer from our business, contact 951-403-5738 or industrial832@gmail.com. Our Greater Houston pickup and appointment-only drop-off arrangements apply to material we review for purchase.