There are several bonding conductors in the CEC:
(Both are part of the bonding system — but they serve different roles.)
What it is:
The main wire that connects non-current-carrying metal parts (like enclosures, raceways, pipes, etc.) to the grounding system.
Think of it as:
The main safety highway that connects metal parts to earth ground or to the main grounding point.
Example:
A #6 copper wire running from your metal panelboard enclosure to the ground bus — that’s a bonding conductor.
What it is:
A shorter bonding wire that connects two metal parts together so they are electrically continuous.
Think of it as:
A bridge between two pieces of metal that might otherwise be electrically isolated.
Types:
CEC Rules: 10-604 (system jumper), 10-614 (equipment jumper)
Example:
A short wire bonding the two ends of a flexible conduit where continuity might otherwise be lost — that’s a bonding jumper.
**Sizing Bonding JUMPERS and CONDUCTORS is the same**
Bonding conductor size is based on the ampacity of the size of the largest ungrounded (live) conductor in the system — this could be a single conductor or the largest in a parallel set.
Example: If the largest conductor feeding your panel is a #3 AWG copper, go to Table(s) 1-4, and find the ampacity--that’s your reference point.
Once you know the size of the largest ungrounded conductor ampacity, go to CEC Table 16 to find the minimum size of the bonding conductor.
The Bonding Conductor cannot be less than the O/C protecting the conductors or Equipment.
OR
IF the largest ungrounded conductor has been UPSIZED due to voltage drop, then you HAVE TO go with that instead of the O/C device.
Once you know the size of the Over-Current Device go to CEC Table 16 to find the minimum size of the bonding conductor.
FUN FACT: If you are trying to figure out Bonding for a Relocatable Structure, you use Table 41
What is the Bonding Conductor size required for a 30 HP, 600-volt, 3-phase squirrel cage motor with a service factor of 1.15 that is operating under normal circumstances and protected by a NTD fuse?
Step 1: What is the question asking for?
Step 2: What do we have?
Step 3: What do we need?
Table 16: 90A is not an option, so we go UP → 100A
What size of aluminum bonding conductor is needed for a 30 HP, 600VAC, 3-phase SCIM protected by a NTD fuse and supplied by a #6awg R90(XLPE)?
Step 1: What is the question asking for?
Step 2: What do we have?
Step 3: What do we need?
Since we calculated a #8awg, but the question says a #6awg…that means it was up-sized due to voltage drop.
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