Sizing charts, wiring schematics, and code summaries for your workday. Search by trade or save the references you use most. No account needed.
Favorites are saved in this browser. Source documents need an internet connection.
7 references
Electrical · Reviewed 2026-10-01
GFCI requirement finder
Common dwelling receptacles in bathrooms, kitchens, basements, laundry areas, garages, and outdoors generally need GFCI protection. Start with NEC 210.8(A), then confirm your locally adopted edition and any exceptions.
Scope: U.S. dwelling units only. Quick lookup for ordinary 120 V, 15 or 20 A general-use receptacles on single-phase circuits rated 150 V or less to ground. Local adoption, equipment rules, and exceptions can change the answer.
Common dwelling locations to check under NEC 210.8(A)
Location
Quick reference
Bathroom
GFCI generally required
Kitchen
Includes receptacles beyond the countertop under the 2023 expansion
Basement
Includes finished and unfinished areas
Laundry area
GFCI generally required
Garage
Check the complete garage and accessory-building provision
Outdoors
Check exceptions and separate equipment requirements
Conditions & source documents
Select the NEC edition adopted for the job, not simply the current calendar year. The 2026 NEC is not automatically in force everywhere.
This finder does not determine requirements for HVAC, EV charging, pools, appliances, commercial premises, or replacement work. Review the applicable sections and current NFPA amendments for those cases.
Record the location, circuit, adopted edition, and inspector guidance with the job before choosing equipment.
Joist span depends on species, grade, size, spacing, and loads. This calculator compares your clear span with a published sleeping-area table for No. 2 lumber at 16-inch centers and a 30 psf live load.
Scope: Limited table lookup: residential sleeping areas, No. 2 lumber, 16 in on center, 30 psf live load, 10 or 20 psf dead load, and L/360 live-load deflection. Not for living areas, decks, roofs, engineered joists, or concentrated loads.
No. 2 joists at 16 in on center · 30 psf live / 10 psf dead load · L/360
Species
2 × 6
2 × 8
2 × 10
2 × 12
Douglas Fir-Larch
10 ft 9 in
14 ft 1 in
17 ft 2 in
19 ft 11 in
Hem-Fir
10 ft 0 in
13 ft 2 in
16 ft 10 in
19 ft 8 in
Southern Pine
10 ft 3 in
13 ft 3 in
15 ft 8 in
18 ft 6 in
Spruce-Pine-Fir
10 ft 3 in
13 ft 6 in
17 ft 2 in
19 ft 11 in
Conditions & source documents
Measure clear span between support faces. The calculator compares your measurement with the table; it does not interpolate or extend the table to other spacing or loads.
Bearing, bracing, connections, holes, notches, member condition, and the building’s eligibility for prescriptive construction still need checking. A span comparison alone does not approve a structure.
For other grades, spacing, uses, or loads, use the complete AWC tables or obtain a project-specific structural design.
For ordinary applications under NEC 240.4(D), the general copper small-conductor overcurrent limits are 15 A for 14 AWG, 20 A for 12 AWG, and 30 A for 10 AWG. These limits are not a complete wire-sizing calculation.
Scope: 14–10 AWG copper only; 2023 NEC reference. General small-conductor protection limits, subject to specific code exceptions. Aluminum, cable assembly rules, correction factors, and load calculations are outside this lookup.
Copper small-conductor reference · NEC 240.4(D)
Gauge
General overcurrent limit
Approx. solid conductor diameter
14 AWG
15 A
0.064 in
12 AWG
20 A
0.080 in
10 AWG
30 A
0.101 in
Conditions & source documents
A 75°C or 90°C ampacity column does not by itself allow a larger breaker for these small conductors.
Check load, continuous-load requirements, termination ratings, wiring method, ambient temperature, conductor grouping, voltage drop, and equipment instructions before choosing a conductor.
Diameter is bare solid copper, not the outside diameter of insulated cable. Do not use it to size conduit.
2021 IPC Table 704.1 sets minimum slopes of ¼ inch per foot for pipe 2½ inches or smaller, ⅛ inch per foot for 3–6 inches, and ¹⁄₁₆ inch per foot for 8 inches or larger. Upstream of a grease interceptor, use at least ¼ inch per foot.
Scope: 2021 International Plumbing Code, Section and Table 704.1. Horizontal drainage piping only. Confirm local adoption and amendments; this is not a UPC, storm drainage, or vent-sizing tool.
Total fall in inches = horizontal run in feet × slope in inches per foot. A 20 ft run at ¼ in per ft needs 5 in of fall.
Measure horizontal run, not diagonal pipe length. Maintain a uniform slope; total fall alone does not establish that the installed pipe has no flat spots.
This checks slope arithmetic only. Pipe capacity, fixture units, venting, cleanouts, and available elevations require separate checks.
Trane codes depend on the model and control board. This reference covers selected S9V2 faults from installer’s guide 18-CE01D1-1E-EN (2016), page 96. For example, E3.2 indicates an open first-stage pressure switch on that control.
Scope: Trane S9V2 models and control described in 18-CE01D1-1E-EN only. Match the unit label, board, and manual revision before using a code meaning. Other Trane furnaces, thermostats, and HVAC systems may use different codes.
Ignition retries exhausted; flame was not established.
E2.2
Too many cycles with flame established and then lost.
E3.1
First-stage pressure switch reported shorted.
E3.2
First-stage pressure switch reported open.
E3.3
Second-stage pressure switch reported shorted.
E3.4
Second-stage pressure switch reported open.
E04
An open limit circuit: thermal, rollout, or reverse-airflow switch.
E05
Flame detected when it should be absent.
Conditions & source documents
Capture the model number, exact display, and symptoms for the service record. A fault identifies a reported condition; it does not prove that a particular part needs replacement.
Do not bypass pressure, rollout, or limit switches, or repeatedly reset a furnace to keep it running. Electrical, gas, and combustion diagnosis belongs with a qualified HVAC technician.
If you smell gas or a carbon monoxide alarm sounds, leave the building and contact emergency services or the gas utility from a safe location.
Supply connects to LINE; unused LOAD terminals remain covered.
Scope: Conceptual connections for Leviton GFNL2, instruction sheet PK-A3081-10-00-2B. Not physical terminal positions or a universal installation diagram.
Connection relationships · Connections, not terminal placement
Supply hot→LINE hot
Supply neutral→LINE neutral
Equipment ground→Device ground / box bonding as required
Conditions & source documents
Disconnect power and verify de-energization. Follow the complete device instructions and test procedure; refer unfamiliar circuits to a qualified electrician.
GFCI protection does not replace grounding or overcurrent protection.
LINE receives the supply. Paired LOAD hot and neutral provide downstream protection.
Scope: Conceptual connections for Leviton GFNL2, instruction sheet PK-A3081-10-00-2B. Not physical terminal positions or a universal installation diagram.
Connection relationships · Connections, not terminal placement
Supply hot→LINE hot
Supply neutral→LINE neutral
Equipment ground→Device ground / box bonding as required
LOAD hot→Downstream hot
LOAD neutral→Downstream neutral
Conditions & source documents
Disconnect power and verify de-energization. Follow the complete device instructions and test procedure; refer unfamiliar circuits to a qualified electrician.
GFCI protection does not replace grounding or overcurrent protection.
These U.S. references have specific editions, equipment models, and table conditions. Confirm local adoption, amendments, and manufacturer instructions. A quick lookup does not establish that a job is code compliant. The wiring diagrams show connection relationships for the named device, not a universal installation plan.
