A cabinet, box, or enclosure’s service conduits are mainly connected and terminated with the bonding bushings. Lay-in lugs allow for easy access to conductors during installation. But most of the time we get confused while installing bonding bushing.
How to install bonding bushings?
Cut it to length and deburr the conduit end to prepare the pipe. Then, install the Bond Bushing over the wires and into the conduit. Close the Bond Bushing and place it in the proper position. Next access the set screw, grounding lug, and hinge screw. Lastly, torque all set screws to UL specs.
Here you’ve only seen a small portion of the iceberg. The entire process may be overwhelming. To help you out, I’ve written up this article.
Let’s get into the topic!
Is It Necessary to Use Bonding Bushings?
A bonding bushing should typically be fitted to maintain electrical connections of the bonding/equipment wiring system. Bonding is different to earthing-grounding.
Because there feeders enter or exit a load center with concentric knockouts. The neutral bus bar should be used to connect bonding bushings.
In some cases, bonding bushings are necessary. However, there are numerous more circumstances in which bonded bushings are superfluous.
Usually, they are used for circuits with voltages more than 250 volts that flow via concentric knockouts. Aside from that, they aren’t required daily in most situations.
A bonding bushing is required if-
- Service conductors are present in your raceway.
- The grounding electrode conductors in your raceway are a good idea. Depending on the GEC performance, you may require one on both ends.
- When your raceway ends, your non-metallic enclosures do, too.
- The circuit exceeds the nominal voltage of 250 V to the ground when your raceway ends with only a few ring knockouts left.
- There is no enclosure at the end of your raceway.
A bonding bushing is not required if-
- Your raceway is non-metallic; therefore, it’s safe.
- A second enclosure with a suitable electrical connection to the raceway is at the other end of your raceway. Except where doing so is essential to the GEC’s operation.
- You don’t have a bonding locknut or a bonding hub. It is possible to attach the EGC using a screw.
- Standard plastic bushings can be used in any of the examples mentioned above.
How to Install Bonding Bushings?
Bonding Bushing does not require a conduit to be threaded onto it. Even in tight installations, the grounding lug is perfectly positioned. It’s done in order to accommodate the grounding wire conduit.
Regardless of whether the conduit is threaded or non-threaded, it can be used. Instead of threading on a bushing to the conduit, this installation uses a nut. For safety’s sake, you should remove the grounding lug. Afterwards, reattach the lug in a small area
Finally, the bushing must be twisted and turned to position the lug to take the ground wire. The bushing eliminates these unnecessary delays, making it the perfect bonding bushing. And it’s the best option for tight places, corners, and many conduits run.
Since it’s part of the bushing, it won’t fall off or get misplaced, making it more secure. A fundamental understanding of bonding bushings is required before beginning the installation process. Here I’ve added them below-
- To keep the bushing firmly in place, the mounting screw features a cone point.
- Secondly, an integrated grounding lug improves the continuity of the ground. Increasing the ground wire range reduces the amount of inventory. For copper or aluminum grounding, this device accepts.
- Insulating nylon covers the whole surface of the bushing, including the corners of the lugs.
- The angle of the bolt screw makes it easier to secure a grounding cable.
- In order to reduce drag and prevent wire damage, insulation is rounded on the outside.
- While installing, the cast “threads” on the other side of the screw tighten the fit.
Step-by-Step Installation Process
Installing bonding bushings is not such challenging work to do. Your hands are more than able to handle this task. After knowing the essential things to work with, you can quickly go for the step-by-step installation.
Step 1: Position the Bond Bushings to the Conductors
Cut the pipe to the desired length and deburr the conduit end to prepare it. You can cut pipes without tools. Make sure the Bond Bushing is positioned correctly around the conductors. And onto the end of the conduit.
Step 2: Remove the Conduit Spacer
Remove the Conduit Spacer from the assembly for Threadless RMC or Threadless IMC sizes 1″ to 2″. Conduit Spacers are needed for 1″ to 2″ EMT to ensure a correct fit.
Step 3: Close the Bond Bushing
To access the set screw, grounding lug, and hinge screw, close the Bond Bushing. Then orient it so that it is easily accessible.
Conduit screws should be loosened enough to allow the two pieces to seal entirely around a conduit. The bushing should be positioned as close to the conduit as practicable.
Step 4: Tighten the Screws
Tighten the conduit set screws after you’ve finished tightening the hinge screw. Retighten all set screws following the UL torque specifications (35 in-lbs).
Step 5: Tighten the Screws on the Grounding or Bonding Conductor
Tighten the set screw on the grounding or bonding conductor to the proper size. Loosening the lug screws to the required UL level of torque is essential. A 35 in-lb torque setting is also recommended for the lug attachment screw.
Here I’ve recommended two best screws to use for you in this step. Check them below-
These screws are well-known in the market and also not too expensive. Your local store will have these readily available to you. In this step also, you may need to check grounding with a multimeter.
My conversation with you today has come to an end. I’ve also covered a few other crucial subjects in this article. Use it to get the job done right in the installation process.
Question: Where should you not use PVC electrical, if possible?
Answer: Avoid putting it in places where it will be exposed to the elements. Because it is not UV-rated and will be damaged. Conductor for electric currents PVC is primarily employed in electrical systems as a conduit for wires and cables.
Question: Are reducing washers suitable for bonding on the manufacturer’s list?
Answer: The Underwriters Laboratories (UL) conducts resistance and current tests on all listed reduction washers. UL 514B and UL 467 both include these tests. A single manufacturer recommends bonding around the washer to prevent falling out of place.
Question: What are Kenny clamps?
Answer: With the Kenny Clamp, you’ll be able to connect your ground and bonding wires safely. The Kenny Clamp (NEC 250.8 and 250.64) secures service panelboard. Also, it secures load center, and switchboard enclosures to the grounding electrode wire conductor.
I hope you have a better understanding of bonding bushings!
Bonding on the service side of a connection cannot be done with locknuts. Don’t try to do this. That’s why you should use proper safety equipment while working.
Have a wonderful day!