"Breaker Breaker 1-9"
I'd Tap That!
Disco Tech
Location and Labels
PV Design Potpourri
100

This occurs when current flows from a secondary power source towards the primary power source

What is backfeed?

100
This type of equipment often limits tap interconnections to load-side only

What is a meter main?

100

The number of switches used per PV System disconnect must be no more than this number

What is 6?

100

This marking would not be found on circuit breakers suitable for backfeeding

What is "line" and "load?"

100

This document is required if a redesign adds or deducts equipment

What is a change order?

200

This principle states that the allowable amperage of a PV breaker can be found with the equation "(Busbar Amps x 1.2) - Main Breaker Amps = Allowed PV Output"

What is the "120% Rule"?

200

NEC 705.11 allows for supply-side interconnections to occur anywhere between these two locations

What are the net meter and the main service disconnect?

200

Both system and equipment disconnects must be rated for these three factors

What are maximum circuit current, available fault current, and maximum voltage?

200

When following the 120% Rule, the back-fed breaker must include a label warning electricians against doing this

What is relocation?

200

Fire safety setbacks for systems over 25% / 33% may be ignored if the arrays are located on this type of building

What is a detached, non-inhabitable structure?

300

This type of service panel, more common in new construction, allows for the PV breaker to be located on either end of the busbar

What is a center-fed panelboard?

300

This device may be used to create a "tap area" if the service equipment will not accommodate a supply-side tap

What is a junction box?

300

According to NEC 705.20, a disconnect is required to separate these from the conductors of other systems

What are source output circuits?

300

According to the NEC, the center of this can be no more than 6' 7" from the floor at its highest position

What is a handled disconnect switch?

300

AHJs in Oregon frequently reject documents because these differ on the A2 - Roof Layout and Aurora Report

What are pitch/slope, azimuth, and lowest TSRF?

400

If the main breaker amperage is less than the busbar amperage, and this rule is followed, then a PV breaker can land anywhere in a panel

What is "Total Sources ≤ Busbar Rating"? 
400

Supply-side conductors, i.e. the conductors running from the POI to the first OCPD, must be greater or equal to this gauge (dependent on materials)

What is 6 AWG Cu and 4 AWG Al?

400

Knife-blade switches and breakers are examples of this type of disconnect

What is a load-break-rated disconnect?

400

Jurisdictions following this must include a disconnect within 10' and line-of-site of the tap, as well as an exterior disconnect for rapid shutdown

What is the Washington Cities Electrical Code?

400

When trenching, both the length of the trench and the size of the conductors must be considered to avoid this issue

What is voltage drop?

500

Increasing the size or re-establishing overcurrent protection are two methods of ensuring safe operation of this electrical equipment

What are feed-through conductors (or feeders)?

500

Using these devices to create a supply-side tap do not require electrical service shutdown, but their bulky size may limit their application in crowded panels

What are insulation-piercing tap splice connectors?

500

Plug connectors and finger-safe fuse holders are examples of this type of equipment, which is not required to disconnect all non-solidly grounded conductors simultaneously 

What is an isolating device?

500

690.15(A) specifies that equipment disconnecting means must be found inside the equipment itself, or follow these two alternate requirements

What is within sight and within 10' of the equipment?

500

6.5' x 2.5' x 3'

What are working space requirements for electrical equipment?

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