The single most confused pair of terms in electrical work. They are not the same thing, they don't do the same job, and mixing them up is how people end up believing metal is "safe" when it isn't.
Say the words "ground" and "bond" to most people and they'll shrug — surely it's the same idea, just different jargon. It isn't. Grounding connects a system to the earth. Bondingconnects metal parts to each other. One is about a reference point. The other is about safety between things a person can actually touch. Confusing them is exactly how someone ends up assuming a "grounded" enclosure is automatically safe to touch — which, on its own, it is not.
Grounding means connecting a system or piece of equipment to the earth itself — through a ground rod, a buried plate, or a metal water pipe. Earth is a genuinely poor conductor (tens or hundreds of ohms at best, at the electrode). Its job is to stabilize the system's voltage relative to the planet and give lightning, static buildup, and utility surges somewhere to dissipate. Earth is not, and never was, the intended path for fault current.
Bonding means connecting conductive parts — enclosures, conduit, motor frames, structural steel — together with low-impedance conductors so they are all held at the sameelectrical potential as each other. That's the part that actually keeps people alive: if every metal surface someone might touch at the same time is forced to the same voltage, there's no potential difference between them, and a person bridging two of them can't become a path for current. Bonding is also what gives fault current a fast, low-resistance route back to the source — which is what lets a breaker trip quickly.
A person is only at risk when their body is the path between two points at different voltages. Earth itself is a poor, inconsistent conductor — two separate ground rods a short distance apart can easily sit at different voltages relative to each other, especially while one is carrying fault current through resistive soil. Bonding removes the danger a completely different way: instead of trying to force every metal part to some absolute voltage, it forces them all to the same voltage as each other, whatever that voltage happens to be at any instant. No difference, no driving force, no current through a person spanning two bonded parts.
False, and it's the reason this pair of terms causes real accidents. "Grounded" only tells you a part is connected to earth somehow — it says nothing about what voltage that part is actually at relative to the other metal things nearby. Two enclosures can both be perfectly, correctly grounded and still sit at meaningfully different voltages during a fault, because earth is resistive and each ground path is independent. Bonding — not grounding to earth — is what guarantees two touchable metal parts stay at the same potential.In practice, code-compliant installations do both: bond everything together, then ground that bonded system to earth once. But it's the bonding, not the earth connection, doing the shock-prevention work.
Explains the difference between grounding (connecting a system to earth, primarily to stabilize voltage and dissipate lightning/surge energy) and bonding (connecting conductive parts to each other so they share the same electrical potential), and why bonding — not the earth connection — is what actually prevents shock between two metal parts.
Grounding connects a system or piece of equipment to the earth through a grounding electrode — a driven rod, buried plate, or ground ring. Earth is a relatively poor and highly variable conductor (resistance at a single rod is commonly tens of ohms, sometimes far more depending on soil moisture and composition). This connection stabilizes the system's voltage relative to the planet and gives lightning strikes, static discharge, and utility-side surges a place to dissipate. It is not designed, and is not adequate, to carry sustained fault current back to the source.
Bonding connects conductive parts — equipment enclosures, conduit, cable trays, structural steel, piping — together with permanent, low-impedance conductors so that all of them are forced to the same electrical potential at all times, including during a fault. Because there is no voltage difference between bonded parts, a person touching two of them simultaneously cannot become a path for current between them. Bonding also happens to provide the low-impedance route that lets fault current be large enough to trip an overcurrent device quickly — the mechanism covered in the companion Concept Explainer on the ground fault return path.
In a correctly installed system, the bonded network of metal parts is itself connected to earth at one point (typically at the service). Because everything traces back to that same physical connection, people conflate "connected to the ground system" with "connected to earth" — but the life-safety property (no potential difference between touchable parts) comes entirely from the bonding, not from the earth connection. Two objects can each be perfectly grounded to earth independently and still have a dangerous voltage between them if they are not bonded to each other.
No. A grounding conductor connects a system to earth for voltage stabilization and surge/lightning dissipation. A bonding conductor (commonly the equipment grounding conductor in a branch circuit, or a bonding jumper between enclosures) connects metal parts to each other so they share the same potential. In practice the same piece of wire in a branch circuit often serves the bonding function under NEC terminology, which is part of why the two terms get blurred.
Yes — if it is grounded through its own independent path but not bonded to other nearby metal parts, it can sit at a different voltage than those parts during a fault. Grounding alone does not guarantee two touchable objects share the same potential; bonding does.
Because two independently grounded objects are not guaranteed to be at the same voltage — earth is resistive and inconsistent, and each ground path behaves differently under fault conditions. Bonding removes that uncertainty by directly tying the objects together, which is a fundamentally different and more reliable guarantee than "each is connected to earth somehow."
No, they serve different purposes and code requires both. The bonded network still needs one connection to earth (the grounding electrode system) to stabilize its voltage relative to the planet and to bleed off lightning and surge energy. Bonding handles safety between touchable parts; grounding handles the system's relationship to earth.
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