TxDOT Item 620 Electrical Conductors: Bid Code Spec, Pricing and Payment Boundaries
Item 620 pays for furnishing and installing electrical conductors, and the hard part isn't the wire, it's knowing which wire belongs to this item at all. The payment section carves out four exceptions, and two of them look identical in the field. Conductor inside an illumination pole gets paid under Item 610. Conductor inside a traffic signal pole gets paid right here. Here are the 4 bid codes that show up most in recent TxDOT lettings, what separates one from the next, and why a run measured by the foot can still be measured wrong.
TxDOT Item 620 Bid Code Variants: What Determines Pricing
The four codes below are a clean grid, two sizes crossed with two types. Straight from the spec on how any of them get measured:
"This Item will be measured by the foot of each single conductor."
Three things decide what you're pricing:
- Conductor size. No. 8 and No. 6 are the two sizes in this data. No. 6 carries about 60% more copper cross-section than No. 8, and it prices about 19% higher on all bids. The price gap is much smaller than the copper gap, which tells you the pull, not the metal, is the bigger part of this number.
- Bare or insulated. This isn't just a jacket. The spec's testing requirement is written specifically around insulated conductor, so the insulated codes carry a compliance obligation the bare codes don't. More on that in the quality gates section.
- Each single conductor, not each run. This is the takeoff trap on Item 620. A 500 ft. run pulling three conductors is 1,500 ft. of pay quantity, not 500. The spec says each single conductor and means it. Get that wrong on takeoff and the error scales with every multi-conductor run on the job.
Item 620 is also a plans quantity item, same as Item 104. You get paid the quantity in the proposal unless an Article 9.2 adjustment applies.
One naming note. Clarement says bid item throughout. TxDOT's own contracts and this spec say pay item, so both point at the same thing and people search both.
TxDOT Item 620 Pricing: Key Takeaways
- Conductor inside a signal pole is paid here. Conductor inside an illumination pole isn't. Same picture in the field, two different items.
- Measurement is by the foot of each single conductor, so a three-conductor run is three times the length, not one.
- Breakaway connectors are furnished, installed, and buried in the per-foot conductor price. A discrete piece of hardware inside a linear rate.
- Testing is in the price too, including verification testing the Engineer can call for and will witness.
- A run that fails the 5 MΩ test gets replaced at no cost to the Department, and the splice rules mean you can't patch your way out of it.
- No. 6 prices about 19% above No. 8, and insulated prices 10% to 20% above bare depending on size.
Cost Factors for TxDOT Item 620 Electrical Conductors
Cost Factors That Vary by Bid Code
Copper cross-section. No. 6 is roughly 60% more copper per foot than No. 8. That's the material step between the size pairs, and it shows up in the pricing below, though at a smaller percentage than the copper difference alone would suggest.
Whether the code is insulated, because the test only applies to insulated runs. The spec ties the 5 MΩ insulation resistance requirement to "each continuous run of insulated conductor." Bare conductor doesn't carry that obligation. So the insulated codes cost more for the insulation and more for the testing and the replacement exposure behind it.
Color requirements, on insulated codes. White is reserved for grounded neutral conductors and green for insulated grounding conductors, and the spec explicitly bans using either color for anything else except control wiring shown on the plans. At Size 4 AWG and larger you can substitute black with tape marking at every accessible location, which is a labor step rather than a material one. Pulling the wrong color is a replacement, not a relabel.
Cost Factors That Apply to Every TxDOT Item 620 Bid Code
Material is MPL-sourced and spec-bound, not commodity wire.
"Provide pre-qualified electrical conductors from the Department's MPL. When required by the Engineer, notify the Department in writing of selected materials from the MPL intended for use on each project."
On top of the MPL, the conductor has to be stranded, rated 600V, approved for wet locations, marked to UL, NEC, and CSA, and furnished per DMS-11040. Price against that list, not against whatever the supply house has on the shelf.
Grounding conductors are stranded, with one exception. The spec requires all grounding conductors Size 8 AWG and larger to be stranded, except the grounding electrode conductor at the electrical service, which is a 6-AWG solid conductor. That's the only solid conductor the spec calls for, and note that conductors connecting the components of electrical services are paid under Item 628, so confirm where that particular conductor lands on your job before you price it here.
You can't splice wherever it's convenient.
"Splice conductors only in junction boxes, ground boxes, and transformer bases, and in poles and structures at the handholes."
No mid-conduit splices. A pull that comes up short doesn't get joined in the raceway, it gets re-pulled. That single sentence is what makes a measurement error on this item expensive rather than annoying.
Pulling has limits. Don't exceed the manufacturer's recommended pulling tension, use the lubricant the manufacturer recommends, and install per NEC. Overpulling damages conductor you then own the replacement on.
TxDOT Item 620 Payment Terms: Subsidiary Work vs. Separately Paid Items
What the unit price covers:
"This price is full compensation for furnishing, installing, and testing electrical conductors; furnishing and installing breakaway connectors; and materials, equipment, labor, tools, and incidentals"
Two things in there are easy to miss. Testing is inside the price, including verification testing the Engineer can require and will witness. And breakaway connectors are furnished and installed on the same per-foot number, a discrete hardware item with no line of its own.
Then the spec carves out four exceptions, and this is the part worth reading twice:
"conductors used in connecting the components of electrical services will be paid for under Item 628, 'Electrical Services'; conductors inside roadway illumination assemblies will be paid for under Item 610, 'Roadway Illumination Assemblies'; conductors inside traffic signal pole assemblies will be paid for under this Item; and conductors used for internal wiring of equipment will not be paid for directly, but will be subsidiary to pertinent Items."
Four conductors, four different answers:
- Service connection conductor. Paid under Item 628.
- Conductor inside a roadway illumination assembly. Paid under Item 610.
- Conductor inside a traffic signal pole assembly. Paid right here, under Item 620.
- Internal equipment wiring. Not paid directly at all, subsidiary to whatever item the equipment belongs to.
The two pole cases are the ones that catch people. Wire inside an illumination pole and wire inside a signal pole are the same physical situation, conductor running up inside a vertical support. The spec sends them to different items. If you learn the illumination rule first and generalize it, that wire inside a pole belongs to the pole's item, you'll price signal pole conductor into Item 610's assemblies and leave a hole in your Item 620 quantity. The spec goes out of its way to say "under this Item" for the signal case specifically, which is a tell that it expects the confusion.
This is the same shape of trap that Item 540 carries on concrete curb, where the material spec points to another item but the payment stays put. A cross-reference to another item tells you where a rule lives, not always where the money goes. Read the payment article, not the materials article, to answer a payment question.
TxDOT Item 620 Quality Gates and Placement Requirements
Item 620 has a real test with a number attached, which puts it closer to Item 432 than to items where the only risk is at installation. It isn't an ongoing performance obligation the way Item 666's retroreflectivity is. It's a one-time gate, but it sits at an expensive point in the sequence.
The gate:
"Test insulation resistance on the conductors before making final connections and ensure each continuous run of insulated conductor has a minimum direct-current (DC) resistance of 5 megohms (MΩ) when tested at 1,000V DC."
Before final connections, on each continuous run, 5 MΩ minimum, tested at 1,000V DC.
The Engineer can widen it.
"The Engineer may require verification testing of all or part of the conductor system. The Engineer will witness these verification tests."
All or part of the system, at the Engineer's call, witnessed. That's schedule time as well as testing time, and it's inside your unit price.
The failure consequence is what makes this expensive.
"Replace conductors exhibiting an insulation resistance of less than 5 MΩ at no additional cost to the Department."
Replace, not repair. And the splice restriction means replacement is a full re-pull of the run, because you can't splice around a bad section inside a conduit. A conductor that fails the test after it's pulled costs you the wire, the labor to pull it out, and the labor to pull new. That's the number to have in mind when you decide how careful to be about pulling tension and lubricant.
Pricing Considerations for Conductor Installation
- Price testing as labor you will perform, not a contingency, since it's required on every insulated run and the Engineer can call for more.
- Carry a re-pull allowance on long or difficult runs, because a failed test can't be spliced out, it has to be replaced end to end.
- Confirm the conductor count per run before takeoff, since pay quantity is per single conductor and a multi-conductor run multiplies.
- Price breakaway connectors into the per-foot rate, not as a separate hardware line, since the payment article puts them there.
TxDOT Item 620 Bid Item Pricing Data
Weighted average unit price across TxDOT lettings over the last 24 months, both across every bid submitted and on the low, winning bid specifically. Each code links to its full pricing page, where you can see the spread by competitor, district, and quantity.
Pricing Analysis: Key Cost Comparisons Across TxDOT Item 620
These four codes are a clean two-by-two, two sizes crossed with bare and insulated, so every comparison changes exactly one variable. That's rare in this data and it makes the numbers unusually readable.
Both variables push the same direction, every time.
Going up a size costs more at both types. Going from bare to insulated costs more at both sizes. No exceptions in the grid, which is not something to take for granted, because Item 540's code pairs ran in opposite directions within the same item. Consistent direction isn't a given.
The size step costs less than the copper suggests. No. 6 carries about 60% more copper cross-section than No. 8, but prices only 19% above it on bare conductor and 30% above on insulated. Copper is a minority of what you're paying for on a per-foot basis. The pull is the rest, and the pull doesn't care much what gauge is on the reel.
The insulation premium is wider on the bigger conductor.
On low bids the two premiums land closer together, 16% on No. 8 and 18% on No. 6. The all-bids spread between 10% and 20% comes mostly from the No. 8 insulated code sitting high relative to its own winning bids, covered next. Don't carry a single insulation premium across sizes without checking the specific pair.
Low-bid discounts vary more than the prices do. The four codes sit in a tight band, $2.10 to $3.00, but the distance between the average bid and the winning bid isn't tight at all.
Insulated No. 8 is the tightest code on the board. Winning bids come in 4% under the average, so there's almost no room between a safe number and a winning number there. Insulated No. 6 gives you three times that room. If you're pricing all four off one markup, that's where it costs you.
Executing TxDOT Item 620: Avoiding Rework and Ensuring Payment
Same spec, laid out as things to actually do on the job.
Rework Triggers Under TxDOT Item 620
- A continuous insulated run testing below 5 MΩ at 1,000V DC, replaced at your cost
- Conductor damaged by exceeding the manufacturer's recommended pulling tension
- Splices made anywhere other than junction boxes, ground boxes, transformer bases, or poles and structures at the handholes
- White or green insulation used on a conductor that isn't a grounded neutral or an insulated grounding conductor
- Grounding conductor Size 8 AWG or larger furnished solid instead of stranded
- Conductor furnished from outside the MPL, or not meeting the 600V wet-location marking requirements
Field Compliance Requirements for TxDOT Item 620
- Notify the Department in writing of selected MPL materials when the Engineer requires it
- Test insulation resistance before making final connections, not after
- Use the manufacturer's recommended lubricant and stay inside the recommended pulling tension
- Tape-mark black conductors at every accessible location where the Size 4 AWG and larger substitution is used
- Splice only at the locations the spec allows, and only as shown on the plans
- Install per NEC throughout
Pay Application Requirements for TxDOT Item 620
- Bill by the foot of each single conductor, not by the foot of run, on every line
- Confirm which item each conductor belongs to before invoicing, service conductors to Item 628, illumination assembly conductors to Item 610, signal pole assembly conductors here
- Never submit internal equipment wiring as its own line. It's subsidiary to the pertinent Item
- Don't invoice breakaway connectors separately, they're inside the conductor unit price
- Keep insulation resistance test records, including any verification testing the Engineer witnessed
- Confirm plans quantity versus field-adjusted quantity before final pay application, since this is a plans quantity item by default
Built for people pricing and executing TxDOT electrical conductor work
Frequently asked questions about TxDOT Item 620
What is TxDOT Item 620, Electrical Conductors?
The TxDOT spec for furnishing and installing electrical conductors, except conductors specifically covered by other Items. It sets the material standard, the splice locations, the insulation resistance test, and the boundary with Items 610 and 628.
How is Item 620 measured?
By the foot of each single conductor. A run carrying three conductors is measured as three times the run length. It's also a plans quantity item, so you're paid the proposal quantity unless an Article 9.2 adjustment applies.
Are conductors inside a light pole paid under Item 620?
No. Conductors inside roadway illumination assemblies are paid under Item 610. Conductors inside traffic signal pole assemblies are paid under Item 620, which is the distinction people get backwards.
Is internal equipment wiring paid separately?
No. It's subsidiary to the pertinent Items, with no direct payment of its own.
Are breakaway connectors a separate bid item?
No. Furnishing and installing them is inside the conductor unit price.
What is the insulation resistance requirement?
Each continuous run of insulated conductor has to show at least 5 megohms of DC resistance when tested at 1,000V DC, tested before final connections. Anything below that gets replaced at no cost to the Department.
Where can conductors be spliced?
Only in junction boxes, ground boxes, transformer bases, and in poles and structures at the handholes, and only as shown on the plans. No mid-conduit splices.
What conductor colors does the spec require?
White for grounded neutral conductors and green for insulated grounding conductors, and neither color may be used for anything else except control wiring shown on the plans. At Size 4 AWG and larger, black with tape marking at every accessible location is allowed instead.
Is this pricing data free to use?
Yes. Every bid item pricing page linked above is free, no account needed.