Let's break down what a tap conductor is in the context of PV interconnection and where it likely applies in your scenario.

What is a Tap Conductor?

A tap conductor, in electrical terms, is a conductor that taps (connects to) a larger, protected conductor (the feeder or branch circuit) without overcurrent protection at the point of the tap. Think of it like branching off a main water line with a smaller pipe without a valve at the point where the smaller pipe connects.

Key Characteristics of Tap Conductors



No Overcurrent Protection at Tap Point

This is the most important defining characteristic. The tap conductor relies on the overcurrent protection device (fuse or circuit breaker) on the main conductor it's tapping into.

Limited Length

Because there's no local overcurrent protection, tap conductors are generally limited in length. This is to ensure that a fault on the tap conductor will cause the main overcurrent protection device to trip quickly and safely. The NEC (National Electrical Code) specifies the permitted lengths of tap conductors, usually relative to the size of the main conductors and the overcurrent protection rating.

Size Requirements

The tap conductor must have an ampacity (current-carrying capacity) that is sufficient for the load it is supplying.

Specific NEC Rules

The NEC (Article 240.21) has specific rules regarding the permitted lengths and ampacity requirements for tap conductors. These rules vary depending on the application.

Applying it to your Diagram

Without seeing the diagram I can't specifically say where the tap conductor is on the diagram. If the diagram shows the components of a typical PV system that would be connected to a source side or load side tap, this should help:

1. Load Side Tap

If we are talking about a typical load side tap, you will have conductors coming from the main service panel to a load, then there will be a tap point that branches from this conductor. The point where the PV conductors connect to this existing load conductor is the tap point.

2. Source Side Tap

If we are talking about a typical source side tap, you will have conductors coming from the main service panel to a overcurrent protective device (breaker) that runs through a disconnect switch. The tap will happen at the disconnect switch, or between the overcurrent protection device and the disconnect switch.

General Considerations for PV Interconnection and Tap Conductors



Source-Side vs. Load-Side Taps

PV systems can be connected to the grid on the "source side" or "load side" of the main overcurrent protective device. Tap rules apply to both.

Inverter Output

The output of the inverter is where tap conductor rules often become critical. The conductors from the inverter to the point where they connect to the main panel or service entrance are often subject to tap rules.*

Rapid Shutdown

While not directly related to tap conductor rules, rapid shutdown requirements can impact how you design the wiring in a PV system.

Disclaimer: I cannot provide definitive electrical design advice. You must consult with a qualified and licensed electrical contractor or engineer who is familiar with the NEC and local electrical codes for specific design and installation instructions for your PV system. They will be able to properly assess the installation and ensure that all wiring, including tap conductors, is installed safely and correctly. Flag for review