PR Tech SpanGuard™ EHV 115 kV+ Marker
Developed for installation on higher voltage lines, SpanGuard EHV power line markers have a special coating and other design features to reduce corona effects that can lead to burning or melting with standard markers. Our EHV markers are available in 24” diameter for up to 230 kV and 36” diameter for up to 345 kV. Routinely installed by helicopter, SpanGuard EHV markers are made of durable ABS with superior color retention and use spiral wire preforms for secure, “line friendly” attachment.
For over 50 years, SpanGuard power line markers have been saving lives and protecting valuable power lines by making them visible to low flying aircraft. Because of their durable construction, easy installation, and “line friendly” performance, SpanGuard power line markers continue to be the choice of utilities around the world.
The FAA advises that 36″ power line markers be used on high transmission lines and hazardous river crossings. Smaller 20″ power line markers are permitted on less extensive power lines or on lines in approaches to airports below 50 feet. Each power line marker should be a solid color—international orange, white, or yellow–and the FAA suggests that alternating colors be used on critical lines to optimize visibility in all seasons. (Orange alone may be difficult to see against fall foliage).
While non-EHV markers have been installed on lines up to 135 kV, corona damage over several years often leads to discoloring, burning, and melting. Atmospheric contaminants and other environmental factors can accelerate the degradation process. For this reason, P&R Technologies recommends that SpanGuard EHV markers be installed on energized lines above 115 kV. EHV markers are designed with a special coating and other features for installation on power lines up to 230 kV (24” diameter marker) or 345 kV (36” diameter marker). The markers are available in international orange, yellow, or white. For high temperature lines up 500 kV, see our SpanGuard AL aluminum markers.
ABS vs Fiberglass:
Our SpanGuard ABS and EHV power line markers are constructed of K-10 ABS, a material that has 15 times the weatherability and color retention of fiberglass. It is also much more durable. Unlike fiberglass markers, our ABS markers will not crack if struck by gunshots.
Spiral Preform Attachment:
All SpanGuard power line markers are securely attached to the conductor or shield wire with spiral formed armor rods. These spiral preforms extend outward from the marker and actually reinforce and protect the conductor at the point of attachment. They are completely slip-proof. To our knowledge, none have ever come off the line. The preforms are matched at time of order to the specific size, type, and diameter of line.
SpanBrite™ Nighttime Option:
SpanBrite reflective tape is an option available with all SpanGuard markers, making them more visible at night for helicopters and small planes. Directional landing lights reflect off the tape, making the marker visible up to 2500 feet away at night (750 feet with a small flashlight). SpanBrite is superior to phosphor paints, which are slow to react.
SpanGuard EHV Assembly & Installation:
SpanGuard power line markers are easy to install on the ground or from a bucket, and they are ideally suited to installation by helicopter. This makes it possible to install markers on otherwise inaccessible line across rivers or deep canyons, or where it is not feasible to take the line out of service.
Two helicopters can install over 100 SpanGuard power line markers in a single 8-hour shift, including refueling time. The markers can be largely assembled on the ground in a “clamshell” configuration with the spiral preform in place. In the air, the preform is ready to wrap around the line and only the three bolts closest to the installer need to be installed. P&R Tech partners with Haverfield Aviation and other helicopter services to coordinate the ordering and installation of markers.
