The Unsung Hero of Pipeline Corrosion Monitoring
Every year, thousands of miles of buried pipelines across the United States are walked by field crews conducting close interval potential surveys. These government-mandated inspections verify that cathodic protection systems are working correctly – that corrosion is being controlled, and that our pipelines remain safe for the communities and environments around them.
At the center of every one of those surveys is a simple but critical piece of equipment: survey trailing wire.
This guide covers everything pipeline operators, corrosion engineers, and CIS contractors need to know about selecting, using, and sourcing copper survey wire – from wire gauge and spool types to pigtail durability and offshore applications.
What Is Survey Wire and What Does It Do?
Survey trailing wire – also called CIS wire, CIPS wire, or close interval survey wire – is the copper conductor that connects the field technician’s reference electrode to the data logger as they walk the pipeline route. As the crew moves along the right-of-way, wire is dispensed from a hip pack or backpack spool, trailing behind and maintaining a continuous electrical circuit.
Every pipe-to-soil potential reading – the core data point of any close interval survey – travels through this wire. Its conductivity, integrity, and mechanical durability directly determine the quality of your survey data.
How Survey Wire Is Used in the Field
A typical CIS involves a technician walking the pipeline right-of-way with a copper/copper sulfate reference electrode pressed to the soil directly above the pipe. The electrode connects by trailing wire to a high-impedance voltmeter or data logger, recording pipe-to-soil potential readings every few feet along the route.
The wire is spooled on a hip pack or backpack dispenser, allowing the technician to move freely while wire plays out behind them. At road crossings, fence lines, stockyards, and other obstacles, the wire must be carefully managed to prevent breaks – the most common cause of unplanned downtime in CIS operations.
Wire Gauge: Matching the Wire to the Job
Survey wire is manufactured in a range of gauges measured by the American Wire Gauge (AWG) standard. Thinner wire (higher AWG) is lighter and provides more footage per spool. Thicker wire (lower AWG) is heavier and more break-resistant.
- Lighter gauge wire: ideal for long-distance surveys across open, low-obstacle terrain
- Heavier gauge wire: preferred for rugged terrain, road crossings, and offshore deployment
At Advance Electrical, we supply survey wire in any gauge and spool to your exact mileage – no standard package sizes that do not fit your project.
Pigtail Connections: The Detail That Makes or Breaks a Survey
If you have run CIS surveys in the field, you know the frustration of a broken pigtail. The pigtail is the connection point between the survey wire and the reference electrode or dispenser. It takes constant mechanical stress from wire tension, terrain drag, and road crossings. When it fails, the entire spool becomes unusable – and the crew stops.
Pigtail failures are the number one cause of unplanned downtime in CIS field operations. A failed connection mid-survey means stopping, finding a replacement spool, and accounting for the data gap. In remote pipeline corridors, this translates directly to delays and added project costs.
Advance Electrical’s pigtail connections are engineered for maximum field durability. Our track record for connection performance under real-world conditions is unmatched in the industry – and it is one of the top reasons CIS contractors keep coming back year after year.
Spool Types and Dispenser Compatibility
Survey wire spools come in different sizes for different dispenser systems. Standard spools fit the hip pack and backpack dispensers used by most onshore CIS crews. Our spools are engineered to fit all industry-standard dispenser equipment. For marine and offshore applications, our large-format options provide the capacity needed for longer runs and heavier gauges:
- Standard spool: fits hip pack and backpack dispensers for onshore surveys
- 8″ x 8″ x 8″ spool: higher footage and gauge capacity for offshore and marine surveys
- 11″ x 10″ x 13″ spool: maximum capacity for large offshore projects
Copper Top vs. Pigtail: Which Connection Is Right for You?
We offer two connection styles to match your electrode type and crew workflow:
- Copper top: a bare copper wire end for direct connection to reference electrode hardware
- Pigtail: a pre-formed, durable connection assembly for quick attachment and maximum field durability
Both are available in any gauge and any footage. Our team helps you determine the right connection for your equipment and conditions before the order ships.
Onshore vs. Offshore: Key Differences
Standard onshore survey wire handles the demands of land-based CIS across varying terrain and extended right-of-way. For offshore and marine surveys, additional requirements apply:
- PVC-coated marine wire for saltwater resistance and UV protection
- Heavier gauges to withstand underwater deployment stresses
- Large-format spool sizes for higher footage capacity in marine applications
Choosing a Survey Wire Supplier: What Actually Matters
Not all survey wire is the same, and not all suppliers can deliver what CIS crews need in the field. When evaluating a vendor:
- Inventory depth: Can they fill large orders without backorders or substitutions?
- Custom spooling: Do they spool in-house, or just pass along pre-packaged product?
- Gauge range: Can they supply any gauge your project requires?
- Pigtail quality: What is their real-world track record for connection durability in the field?
- Lead times: Can they ship fast enough to keep your project on schedule?
- Technical expertise: Do their staff understand CIS requirements and project specifications?
The Advance Electrical Difference
Survey wire is our core product – the one we have built our reputation on for over 40 years. When you order from Advance Electrical, you are working with a team that has spent four decades focused specifically on cathodic protection materials and the real-world needs of CIS survey operations.
In 2025 alone, we sold 25,910 miles of survey wire. That number reflects the trust that pipeline operators and CIS contractors across the country place in our product and our team.
- Largest inventory of copper survey wire in the industry
- In-house spooling – any gauge, any mileage
- Copper top and pigtail connection options
- Onshore and offshore configurations available
- PVC-coated marine wire for saltwater environments
- Industry-leading pigtail durability
- Quick lead times
- Direct copper sourcing from a trusted manufacturer
- Knowledgeable team with 40 years of CP industry expertise
Ready to discuss your next CIS project? Contact Advance Electrical Co. at (936) 588-4419 or visit advanceelectricalco.com. We will help you get the right wire on the right spool before your crew hits the field.
