Explain Panel Schedule

A panel schedule is handed to the architect as a coordination document and read as a wall of numbers. Three things in it are architectural decisions: where the panel goes, how much space it and its clearance take, and whether there is room to add anything later.

Inputs the command needs

1. The schedule, complete, including the header block and any notes.
2. The plan, showing the panel's location and what is around it.
3. The code text on working clearance, if a layout check is wanted.

Workflow

Step 1 — Explain the header

The header carries more architectural information than the circuit list:

• Voltage and phase. What the panel distributes, and in plain terms what that means for what it can serve.
• Main breaker or main lugs. Whether the panel can be switched off at itself, which matters for maintenance and for where it can be.
• Bus rating and main rating. The ceiling on what the panel can carry.
• Fed from. Where its supply comes from, which is a route through the building that has to exist.
• Mounting. Surface or recessed. Recessed needs wall depth and that depth is often more than the wall provides, especially in a rated wall.
• Location. As stated, against what the plan shows.

Step 2 — Explain the circuit list

• Each row is a circuit: a breaker, a size, and what it serves.
• Odd and even numbering runs down two columns because the panel is fed by two or three phases alternating down the bus. Explain why the numbering looks strange.
• Poles: single, double, triple, and what each is typically for.
• Spares and spaces are different things. A spare is a breaker installed and not connected; a space is a slot with no breaker. Say how many of each, and say that a schedule showing neither has no room to grow without a new panel.
• Notes, and anything marked as future, by others, or existing to remain.

Step 3 — Explain the load summary

• Connected load is everything added up as though it all ran at once.
• Demand load is connected load after factors are applied, because it does not all run at once. The factors come from the code and from the engineer.
• Say which figure the panel and the feeder are sized against.
• Say what the difference between them implies: a large gap is normal and a small one means little diversity was assumed.

Never state a demand factor. Say the engineer applied them and name the figures as given.

Step 4 — Translate into architecture

The point of the exercise:

Question	What the schedule says	What to check
Where does it go?	Location as stated	Against the plan
How much wall?	Panel dimensions, from the schedule or the cut sheet	Wall length and depth
Recessed or surface?	Mounting	Wall depth, and whether the wall is rated
What cannot be built in front?	Working clearance	Quote the code; it is a keep-clear zone with dimensions and it is not negotiable
Can it be in this room?		Some rooms are not permitted to contain panels; quote the code
Where does the feeder run?	Fed from	A route through the building, and it needs space
Room to grow?	Spares and spaces	If none, adding anything later means a new panel and a new location

Working clearance is the one that gets built over. It is a volume in front of the panel, it appears on no architectural drawing by default, and joinery, storage and equipment end up in it.

Step 5 — Report

The header in plain English, the circuit list explained, the load summary, then the architectural table with everything that has to be checked against the plan.

List what could not be answered from the schedule alone and who to ask.

Rules

• Never state a clearance, a demand factor, or a code requirement.
• Never check the electrical design.
• Distinguish spares from spaces, every run.
• Say which figure the panel is sized against.
• Name the working clearance as a keep-clear volume and say it is code text to quote.
• Point at the engineer for anything the schedule does not answer.

Anti-patterns

• Explaining the circuits and not the header, which is where the architecture is.
• Treating spares and spaces as the same thing.
• Recalling a working clearance dimension.
• Ignoring recessed mounting depth in a rated wall.
• Reading the connected load as the demand load.
• Checking whether the panel is correctly sized.
• Treating "fed from" as somebody else's problem. It is a route through the building.