Part of working as an electrician is to ensure the wiring installed is safe and in compliance with the law, but accidents can still happen. Unfortunately, when working with electricity, such accidents can have serious consequences. Whether you’re new to the industry or simply looking for a refresher, these are the four worst grounding mistakes to avoid.
Lack of Proper Grounding When Installing Low-Voltage Equipment
Even low-voltage equipment such as satellite dishes and telephone lines require proper grounding to be safe. Satellite dishes are considered antenna systems and must follow Article 810 according to the National Electric Code.
This means it must have an antenna discharge unit somewhere between the lead-in conductors’ points of entrance and the receiver. Ideally, it will be as close as possible to the points of entrance. It cannot be installed near combustible material or anything else deemed a hazard. Additionally, the grounding electrode conductor must be in good shape. It can’t be too long or too short, have excessive bends or use unlisted clamps.
Not Properly Replacing Non-Grounding Receptacles
Older homes often have non-grounding receptacles. Although the NEC doesn’t require replacement of them, many electricians still choose to replace these old receptacles with new, grounding units. However, this only makes sense if done properly.
The NEC is strictly against several actions that some electricians take. Never hook up a new grounding receptacle unless you can complete the entire job.
You don’t want a future electrician to assume he or she is protected when the receptacle is non-functioning. Don’t use a short jumper to connect the green grounding terminal to the grounded neutral conductor. Not only does it not comply with NEC standards, it is also quite dangerous because it can make voltage appear on both ground and neutral wires. Instead, choose from the three methods approved by the NEC: run a new branch circuit to the panel, use a GFCI to replace the two-prong receptacle or if it isn’t feasible to acquire a ground, replace the old non-grounding receptacle with a new one.
Incorrectly Connecting the System Neutral and the Equipment-Grounding Conductor
It is important to use the main bonding jumper — or a system bonding jumper if the system is separately derived — to connect the grounded neutral conductor to the noncurrent-carrying enclosures or equipment. The connection must be made at the service disconnecting means.
You should receive a screw or another type of bonding jumper in the packaging when you purchase a new entrance panel. Install it only if it will be used as part of service equipment. If the box is a subpanel with a 4-wire feeder, never install a main bonding jumper. Redundant connections of equipment-grounding conductors and grounded neutrals can cause a circulating current and the clashing of voltage on metal tools. Instead, connect them at the service disconnect and then separate them. It is okay to connect additional ground rods along the conductor but do not connect them to the grounded neutral.
Not Properly Bonding Equipment Ground to Water Pipe
Ensure proper bonding of any equipment ground to a cold-water pipe. Avoid screw clamps or other methods of improvisation because they do not provide permanent bonding. Never simply wrap the wire around the pipe or omit bonding altogether.
As in any industry, methods and technologies used in the electrical industry evolve over time. Consider taking continuing education classes when available to further educate employees as well as protect them and the public when working on electrical jobs.