Do You Know About Testing Your Bucket Truck’s Upper Controller?
If you own a bucket truck, you’ve likely heard terms like “joystick” or “ISO-Grip.” But would you recognize the term “upper controller”? Most bucket truck owners aren’t aware that these controllers, officially termed “Upper Controls with High Electric Resistance Components” by ANSI A92.2, require regular testing.
The upper controller, located at the platform (or bucket), enables operators to precisely maneuver the boom with ease. Altec’s registered trademark “ISO-Grip” often becomes the default name for this component, even when referring to similar parts from other manufacturers. Regardless of its name, if your upper controller is labeled as “insulating,” testing it is not optional—it’s essential.
Upper Controller with dust boot covering in place
Upper Controller with dust boot pulled back, exposing fiberglass insulating components
What Does ANSI A92.2-2021 Require?
The ANSI A92.2-2021 standard governs the manufacture and testing of aerial lift devices. Section 8.2.4(17) specifically addresses upper controllers:
“If the aerial lift device has upper controls equipped with high electrical resistance components and the manufacturer so indicates, they shall be maintained as high electrical resistance components and shall be electrically tested per section 5.4.3.6.”
Inside these controllers are fiberglass components designed to protect operators from electric shock if the platform contacts an energized source. Testing ensures that these components maintain their insulating properties.
Entrance and exit from the electric current. Notice the singed spot of fiberglass at the top, and the arching at the bottom. Just above the arching at the bottom was where we dug into the fiberglass.
Again, the entrance and exit points. The lightly shaded green line connecting the two points traces the path of electrical burning. May be a little harder to see in this picture, but once again you can see the spot where we’ve dug into the fiberglass.
Side profile picture of the component. In this picture you can really see the raised line of fiberglass, that connects entry to exit, where the electricity punctured the fiberglass, travelled down and out of the bottom.
This really is an amazing picture, and illustrates the dangers of high votlage!
Real-World Example: When Testing Prevented a Potential Hazard
During a routine inspection for a customer, JM found a failing upper controller handle that did not meet dielectric testing requirements. Thanks to prompt notification and a quick replacement by the manufacturer, the handle assembly was swapped, retested, and certified on-site, allowing the truck to return to service safely.
Upon further inspection of the failed handle, we discovered the cause: an electric current had punctured the fiberglass, creating a path to the metal structure. This extreme case underscores the importance of regular testing.
Key findings included:
- Entry and Exit Points: Burn marks in the fiberglass where electricity traveled through.
- Carbon Trail: Evidence of electrical burning underneath the fiberglass surface.
- Fiberglass Damage: Raised, scorched lines showing the path of the current.
Why Testing Matters
These insulating components are critical for operator safety, protecting against electric shocks even when gloves are worn. Regular cleaning, servicing, inspection, and testing are mandated by ANSI standards to maintain their resistive properties.
- Frequent Inspections: Include cleaning and visual checks.
- Periodic Inspections: Involve thorough testing by certified providers.
Your Testing Provider Should Cover This
When selecting a testing provider, ensure they conduct dielectric tests on all components, including upper controllers. If your current provider skips this step, it may be time to reconsider.
Comprehensive Testing with JM
JM specializes in dielectric testing for bucket trucks and diggers, adhering to ANSI A92.2 and A10.31 standards. Protect your operators and equipment by ensuring every component is tested, including the often-overlooked upper controllers.
Schedule Your Next Test
Don’t wait until it’s too late. Prioritize safety by contacting JM for reliable testing services and compliance with industry standards.
Author:
Brandon B. De Ramus
June 23, 2023
