vault backup: 2025-10-07 16:32:57

.obsidian/plugins/obsidian-excalidraw-plugin/data.json

@@ -39,9 +39,9 @@
   "dynamicStyling": "colorful",
   "isLeftHanded": false,
   "iframeMatchExcalidrawTheme": true,
-  "matchTheme": false,
+  "matchTheme": true,
-  "matchThemeAlways": false,
+  "matchThemeAlways": true,
-  "matchThemeTrigger": false,
+  "matchThemeTrigger": true,
   "defaultMode": "normal",
   "defaultPenMode": "never",
   "penModeDoubleTapEraser": true,

.obsidian/plugins/recent-files-obsidian/data.json

@@ -9,24 +9,56 @@
       "path": "README.md"
     },
     {
-      "basename": "nfpa-70_article-210_branch-circuits",
+      "basename": "stochastic-branch-takeoff",
-      "path": "nfpa-70_article-210_branch-circuits.md"
+      "path": "stochastic-branch-takeoff.md"
     },
     {
-      "basename": "nfpa-70_article-215_feeders",
+      "basename": "electrical",
-      "path": "nfpa-70_article-215_feeders.md"
+      "path": "electrical.md"
     },
     {
-      "basename": "nfpa-70_article-220_load-calculations",
+      "basename": "full-takeoff",
-      "path": "nfpa-70_article-220_load-calculations.md"
+      "path": "full-takeoff.md"
     },
     {
-      "basename": "nfpa-70_article-310_conductors_for_general_wiring",
+      "basename": "nfpa-70_314_boxes",
-      "path": "nfpa-70_article-310_conductors_for_general_wiring.md"
+      "path": "nfpa-70_314_boxes.md"
     },
     {
-      "basename": "nfpa-70_article-110_requirements-for-electrical-installations",
+      "basename": "nfpa-70_450_transformers",
-      "path": "nfpa-70_article-110_requirements-for-electrical-installations.md"
+      "path": "nfpa-70_450_transformers.md"
+    },
+    {
+      "basename": "nfpa-70_430_motors",
+      "path": "nfpa-70_430_motors.md"
+    },
+    {
+      "basename": "nfpa-70_310_conductors_for_general_wiring",
+      "path": "nfpa-70_310_conductors_for_general_wiring.md"
+    },
+    {
+      "basename": "nfpa-70_220_load-calculations",
+      "path": "nfpa-70_220_load-calculations.md"
+    },
+    {
+      "basename": "nfpa-70_215_feeders",
+      "path": "nfpa-70_215_feeders.md"
+    },
+    {
+      "basename": "nfpa-70_210_branch-circuits",
+      "path": "nfpa-70_210_branch-circuits.md"
+    },
+    {
+      "basename": "nfpa-70_110_requirements-for-electrical-installations",
+      "path": "nfpa-70_110_requirements-for-electrical-installations.md"
+    },
+    {
+      "basename": "alternating-current",
+      "path": "alternating-current.md"
+    },
+    {
+      "basename": "construction-estimating",
+      "path": "construction-estimating.md"
     },
     {
       "basename": "idea",
@@ -48,10 +80,6 @@
       "basename": "fixtures",
       "path": "fixtures.md"
     },
-    {
-      "basename": "full-takeoff",
-      "path": "full-takeoff.md"
-    },
     {
       "basename": "portable-tools",
       "path": "portable-tools.md"
@@ -72,14 +100,6 @@
       "basename": "this-notebook",
       "path": "this-notebook.md"
     },
-    {
-      "basename": "electrical",
-      "path": "electrical.md"
-    },
-    {
-      "basename": "3-phase-power",
-      "path": "3-phase-power.md"
-    },
     {
       "basename": "accubid-setup",
       "path": "accubid-setup.md"
@@ -136,10 +156,6 @@
       "basename": "90-day-performance-review",
       "path": "90-day-performance-review.md"
     },
-    {
-      "basename": "construction-estimating",
-      "path": "construction-estimating.md"
-    },
     {
       "basename": "favorite-quotes",
       "path": "favorite-quotes.md"
@@ -183,14 +199,6 @@
     {
       "basename": "functional-estimating",
       "path": "functional-estimating.md"
-    },
-    {
-      "basename": "estimating-philosophy",
-      "path": "estimating-philosophy.md"
-    },
-    {
-      "basename": "construction-estimating-software",
-      "path": "construction-estimating-software.md"
     }
   ],
   "omittedPaths": [],

alternating-current.md

@@ -6,24 +6,107 @@ tags:
   - topic/electrical
   - type/encyclopedia
 ---
-# 3 Phase Power
+# Alternating Current
+
+[Alternating current (AC)](https://en.wikipedia.org/wiki/AC_power)
+is electric current that reverses direction periodically.
+The voltage and current in an AC circuit oscillate in a sinusoidal manner.
+The frequency of the oscillation is the number of complete cycles per second measured in hertz (Hz).
+The frequency of the AC power grid in the United States is 60 Hz.
+
+* Ungrounded conductor - "Hot"
+* Grounded conductor - "Neutral"
+
+## 3-Phase Power
 
 The conductors between a voltage source and a load are called lines,
 and the voltage between any two lines is called line voltage.
 The voltage measured between any line and neutral is called phase voltage.
 
-%%
-
-## Scratch
-
 * Poles vs Phases vs Wires
 
-3Ø = 3PH 3W
+* 3Ø = 3PH 3W
-3ØY = 3PH 4W
+* 3ØY = 3PH 4W
 
-> Phase abbreviations
+> [!info] Phase Abbreviations
 > * PH
 > * Φ (capital phi)
 > * Ø (latin O with stroke)
 
-%%
+208Y/120V
+480Y/277V
+
+### Voltage Systems
+
+120/240V 1-Phase 3-Wire:
+- 120V 1-Phase 2-Wire # Line to Neutral
+- 240V 1-Phase 2-Wire # Line to Line
+
+120/208V 3-Phase 4-Wire:
+- 120V 1-Phase 2-Wire # Line to Neutral
+- 208V 1-Phase 2-Wire # Line to Line
+- 208V 3-Phase 3-Wire # Line to Lines
+
+277/480V 3-Phase 4-Wire:
+- 277V 1-Phase 2-Wire # Line to Neutral
+- 480V 1-Phase 2-Wire # Line to Line
+- 480V 3-Phase 3-Wire # Line to Lines
+
+wiring-configurations:
+- 1-Phase 2-Wire # Line to Neutral or Line to Line
+- 1-Phase 3-Wire # Line to Line and Line to Neutral
+- 3-Phase 3-Wire # Line to Lines
+- 3-Phase 4-Wire # Line to Lines and Line to Neutral
+
+## Active and Reactive Power
+
+As a consequence of the periodic nature of AC,
+and the electromagnetic "inertia" of inductance and capacitance,
+inherent of all matter,
+the power in an AC circuit is divided into two components:
+
+- **Active Power**
+  (abbreviated $P$, measured in watts)
+  also known as real power, is power that *does work*. 
+
+- **Reactive Power**
+  (abbreviated $Q$, measured in volt-amperes reactive (VAR))
+  transfers no net energy to the load.
+
+derived from these components are others:
+
+- **Complex Power**
+  (abbreviated $S$, measured in volt-amperes (VA))
+  is the vector sum of the active and reactive components.
+  It is "complex" because it exists on the real and imaginary axes
+  of active and reactive power respectively.
+
+- **Apparent Power**
+  (abbreviated $|S|$, measured in volt-amperes (VA))
+  is the magnitude of the complex power vector.
+
+- **Power Factor**
+  (abbreviated $\text{PF}$, unitless)
+  is the ratio of active power to apparent power.
+
+$$
+P = S \times \text{PF}, \quad S = \frac{P}{\text{PF}}, \quad PF = \frac{P}{\text{S}}
+$$
+
+### Power Factor Correction
+
+Capacitance and inductance can both be measured in VAR,
+but their effects cancel each other out rather than add.
+
+## Motors
+
+1hp = 746 watts
+
+full-load current (FLC) / full-load amperes (FLA)
+
+minimum circuit ampacity (MCA)
+
+$$
+\text{MCA} = 1.25 \times \text{FLC}
+$$
+

conductor-sizing.md

@@ -9,14 +9,18 @@ tags:
 ---
 # Conductor Sizing
 
+Conductors are sized to be suitable for the load,
+overcurrent protection is sized to protect the conductors.
+
 ## "The 80% Rule"
 
 "The 80% Rule" is a rule of thumb
 referring to a common convention of several articles
 including:
 
-- [[nfpa-70_article-210_branch-circuits#210.19(A)(1) General.]]
+* [[nfpa-70_210_branch-circuits#210.19(A)(1) General.]]
-- [[nfpa-70_article-215_feeders#215.2(A)(1) General.]]
+* [[nfpa-70_215_feeders#215.2(A)(1) General.]]
+* [[nfpa-70_430_motors#430.22 Single Motor.]]
 
 which paraphrased states:
 
@@ -45,17 +49,26 @@ $$
 $$
 
 but the 180VA per yoke load specified in
-[[nfpa-70_article-220_load-calculations#220.14(I) Receptacle Outlets.|220.14(I)]]
+[[nfpa-70_220_load-calculations#220.14(I) Receptacle Outlets.|220.14(I)]]
 is specifically for calculating service and feeder sizing.
 
-Per [[nfpa-70_article-210_branch-circuits#210.19(A)(1) General.|210.19(A)(1)]]
+Per [[nfpa-70_210_branch-circuits#210.19(A)(1) General.|210.19(A)(1)]]
 a receptacle branch circuit's load
 is the load of the equipment intended to be served by it.
 
+Where general-use receptacles are provided
+without specific equipment in mind,
+circuits will be engineered at the minimum load.
+If a receptacle circuit's load is a whole multiple of 180VA
+there's a good chance that's the number of devices,
+or at least was at some point in the design.
+
 ## Feeders
 
-> [!cite] 250.122 Size of Equipment Grounding Conductors
+> [!cite] NEC Article 250 (emphasis added)
-> **(A) General.** Copper, aluminum, or copper-clad aluminum
+> ### 250.122 Size of Equipment Grounding Conductors
+> #### (A) General.
+> Copper, aluminum, or copper-clad aluminum
 > equipment grounding conductors of the wire type
 > shall not be smaller than shown in Table 250.122,
 > but in no case shall they be required to be larger
@@ -73,8 +86,10 @@ are in contradiction to this idea.
 
 Given a minimum ampacity, find all valid configurations.
 
-> [!cite] 310.10(H) Conductors in Parallel.
+> [!cite] NEC Article 310 (emphasis added)
-> **(1) General.** Aluminum, copper-clad aluminum, or copper conductors,
+> #### 310.10(H) Conductors in Parallel.
+> ##### (1) General.
+> Aluminum, copper-clad aluminum, or copper conductors,
 > for each phase, polarity, neutral, or grounded circuit
 > shall be permitted to be connected in parallel
 > (electrically joined at both ends)
@@ -101,31 +116,64 @@ either for spec requirements or conduit fill considerations.
 ## Voltage Drop
 
 $$
-V_d = \frac{ I \times R \times L \times M }{ P }
+V_d = I \times R \times L \times M
 $$
 
 where
-- $V_d$ = Voltage Drop in volts ($V$)
+* $V_d$ = Voltage Drop in volts ($V$)
-- $I$ = Current in Amperes ($A$)
+* $I$ = Current in Amperes ($A$)
-- $R$ = Linear resistance in ohms per foot ($\Omega\text{ft}^{-1}$)
+* $R$ = Feeder linear resistance in ohms per foot ($VA^{-1}\text{ft}^{-1}$)
-- $L$ = Length of wire one way in feet ($\text{ft}$)
+* $L$ = Length of wire one way in feet ($\text{ft}$)
-- $M$ = Multiplier
+* $M$ = Multiplier
-  - $2$ for 1-phase
+  * $2$ for 1-phase
-  - $\sqrt{3}$ for 3-phase
+  * $\sqrt{3}$ for 3-phase
-- $P$ = Number of parallel runs
 
 It is often more useful to know the maximum length
 a certain wiring configuration is suitable for.
 
 $$
-L = \frac{ V_d }{ I \times M } \times \frac{ P }{ R }
+L = \frac{ V_d }{ I \times M } \times \frac{1}{R}
 $$
 
-- $L$ = Max length of wire one way in feet ($\text{ft}$)
+* $L$ = Max length of wire one way in feet ($\text{ft}$)
-- $\frac{ V_d }{ I \times M }$ = Max circuit resistance in ohms ($\Omega$)
+* $\frac{ V_d }{ I \times M }$ = Max circuit resistance in ohms ($VA^{-1}$)
-- $\frac{ P }{ R }$ = ??? in feet per ohm ($\text{ft}\Omega^{-1}$)
 
 > [!info] Ohm's Law
+>
 > $$
 > V = I \times R, \quad R = \frac{ V }{ I }, \quad I = \frac{ V }{ R }
 > $$
+
+> [!important]
+> "Current" is not the OCPD rating,
+> but the actual load.
+
+## Transformers
+
+$$
+I = \frac{S}{ \sqrt{3} \times V \times E }
+$$
+
+* $I$ = nameplate current rating
+* $S$ = nameplate kVA rating
+* $V$ = feeder voltage
+* $E$ = efficiency
+
+## Parallel Runs
+
+$$
+\frac{1}{R_{\text{eq}}} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} + \dots
+$$
+
+where $R_1 = R_n$:
+
+$$
+\begin{align*}
+\frac{1}{R_{\text{eq}}} &= P \times \left(\frac{1}{R_1}\right) \\
+                        &= \frac{P}{R_1} \\
+          R_{\text{eq}} &= \frac{R_1}{P}
+\end{align*}
+$$
+
+where
+* $P$ = Number of parallel runs

electrical.md

@@ -48,10 +48,29 @@ Wiring devices and their wall plates are a common target of [[gold-plating]].
 
 `COMMON ASSEMBLIES`/`MECHANICAL CONNECTIONS ...`/
 
-##### CU/IP
+##### Roof Mounted Equipment
 
-* Units Condensing Unit
+Unit condensing units
-* Mechanical Connection
+
+.../`CONDENSOR HOME RUNS`
+
+.../`CU CONDENSER SLEEVE W/ FLEX - NO HMRN WIRE`
+
+`NO SLEEVE`:
+Routed through a "doghouse"
+(a large weatherproof opening)
+with several other feeds.
+Used where drilling openings for individual sleeves
+would be impractical.
+
+`PVC SLEEVE`, `EMT SLEEVE`:
+Routed up through the roof,
+(optionally through a disconnect)
+with flex to the equipment.
+
+Equipment Racks: 20 disconnects per rack
+
+`DISTRIBUTIION`/`TRAPEZE RACK SUPPORT ...`/`...`
 
 ##### Trash Chute
 

nfpa-70_210_branch-circuits.md

@@ -119,7 +119,7 @@ shall determine the circuit rating.
 Branch-circuit conductors shall have an ampacity
 not less than the larger of 210.19(A)(1)(a) or (A)(1)(b)
 and comply with
-[[nfpa-70_article-110_requirements-for-electrical-installations#110.14(C) Temperature Limitations.|110.14(C)]]
+[[nfpa-70_110_requirements-for-electrical-installations#110.14(C) Temperature Limitations.|110.14(C)]]
 for equipment terminations.
 
 * (a) Where a branch circuit supplies continuous loads
@@ -127,13 +127,13 @@ for equipment terminations.
     the minimum branch-circuit conductor size
     shall have an ampacity not less than the noncontinuous load
     plus 125 percent of the continuous load in accordance with
-    [[nfpa-70_article-310_conductors_for_general_wiring#310.14 Ampacities for Conductors Rated 0 Volts – 2000 Volts.|310.14]].
+    [[nfpa-70_310_conductors_for_general_wiring#310.14 Ampacities for Conductors Rated 0 Volts – 2000 Volts.|310.14]].
 
 * (b) The minimum branch-circuit conductor size
     shall have an ampacity not less than the maximum load to be served
     after the application of any adjustment
     or correction factors in accordance with
-    [[nfpa-70_article-310_conductors_for_general_wiring#310.15 Ampacity Tables.|310.15]].
+    [[nfpa-70_310_conductors_for_general_wiring#310.15 Ampacity Tables.|310.15]].
 
 ##### 210.19(A)(2) Branch Circuits with More than One Receptacle.
 

nfpa-70_215_feeders.md

@@ -38,7 +38,7 @@ and shall comply with 110.14(C).
     shall have an ampacity not less than the maximum load to be served
     after the application of any adjustment or correction factors
     in accordance with
-    [[nfpa-70_article-310_conductors_for_general_wiring#310.14 Ampacities for Conductors Rated 0 Volts – 2000 Volts.|310.14]].
+    [[nfpa-70_310_conductors_for_general_wiring#310.14 Ampacities for Conductors Rated 0 Volts – 2000 Volts.|310.14]].
 
 Exception No. 1:
 If the assembly, including the overcurrent devices protecting the feeder(s),

nfpa-70_220_load-calculations.md

@@ -117,8 +117,8 @@ A single piece of equipment consisting of a multiple receptacle
 comprised of four or more receptacles
 shall be calculated at not less than 90 volt-amperes per receptacle.
 This provision shall not be applicable to the receptacle outlets
-specified in [[nfpa-70_article-210_branch-circuits#210.11(C)(1) Small-Appliance Branch Circuits.|210.11(C)(1)]]
+specified in [[nfpa-70_210_branch-circuits#210.11(C)(1) Small-Appliance Branch Circuits.|210.11(C)(1)]]
-and [[nfpa-70_article-210_branch-circuits#210.11(C)(2) Laundry Branch Circuits.|(C)(2)]].
+and [[nfpa-70_210_branch-circuits#210.11(C)(2) Laundry Branch Circuits.|(C)(2)]].
 
 #### 220.14(J) Dwelling Units.
 

nfpa-70_314_boxes.md

@@ -1,11 +1,25 @@
 ---
 id:
-aliases: []
+aliases:
+  - nec-314
 tags:
   - authorship/other
+  - destiny/uncertain
+  - status/incomplete
   - topic/electrical
+  - type/encyclopedia
 ---
-# 314.28 Pull and Junction Boxes and Conduit Bodies.
+# Article 314 Outlet, Device, Pull, and Junction Boxes; Conduit Bodies; Fittings; and Handhole Enclosures
+
+## Part I. Scope and General
+
+<!-- TODO: TEXT OMITTED -->
+
+## Part II. Installation
+
+<!-- TODO: TEXT OMITTED -->
+
+### 314.28 Pull and Junction Boxes and Conduit Bodies.
 
 Boxes and conduit bodies used as pull or junction boxes
 shall comply with 314.28(A) through (E).
@@ -14,7 +28,7 @@ shall comply with 314.28(A) through (E).
 > Terminal housings supplied with motors shall comply with
 > the provisions of 430.12.
 
-## (A) Minimum Size.
+#### (A) Minimum Size.
 
 For raceways containing conductors of 4 AWG or larger that are required to be insulated,
 and for cables containing conductors of 4 AWG or larger,
@@ -24,14 +38,14 @@ Where an enclosure dimension is to be calculated based on the diameter of enteri
 the diameter shall be the metric designator (trade size)
 expressed in the units of measurement employed.
 
-### (1) Straight Pulls.
+##### (1) Straight Pulls.
 
 In straight pulls,
 the length of the box or conduit body
 shall not be less than eight times the metric designator (trade size)
 of the largest raceway.
 
-### (2) Angle or U Pulls, or Splices.
+##### (2) Angle or U Pulls, or Splices.
 
 Where splices or where angle or U pulls are made,
 the distance between each raceway entry inside the box or conduit body
@@ -58,7 +72,7 @@ When transposing cable size into raceway size in 314.28(A)(1) and (A)(2),
 the minimum metric designator (trade size) raceway
 required for the number and size of conductors in the cable shall be used.
 
-### (3) Smaller Dimensions.
+##### (3) Smaller Dimensions.
 
 Listed boxes or listed conduit bodies
 of dimensions less than those required in 314.28(A)(1) and (A)(2)
@@ -93,24 +107,24 @@ as part of the product listing.
 > the applicable product standards evaluate the fill markings covered here
 > based on conductors with Type XHHW insulation.
 
-## (B) Conductors in Pull or Junction Boxes.
+#### (B) Conductors in Pull or Junction Boxes.
 
 In pull boxes or junction boxes having any dimension over 1.8 m (6 ft),
 all conductors shall be cabled or racked up in an approved manner.
 
-## (C) Covers.
+#### (C) Covers.
 
 All pull boxes, junction boxes, and conduit bodies
 shall be provided with covers compatible with the box or conduit body construction
 and suitable for the conditions of use.
 Where used, metal covers shall comply with the grounding requirements of 250.110.
 
-## (D) Permanent Barriers.
+#### (D) Permanent Barriers.
 
 Where permanent barriers are installed in a box,
 each section shall be considered as a separate box.
 
-## (E) Power Distribution Blocks.
+#### (E) Power Distribution Blocks.
 
 Power distribution blocks shall be permitted
 in pull and junction boxes over 1650 cm3 (100 in.3)
@@ -120,32 +134,38 @@ and where the installation complies with 314.28(E)(1) through (5).
 > [!exception]
 > Equipment grounding terminal bars shall be permitted in smaller enclosures.
 
-### (1) Installation.
+##### (1) Installation.
 
 Power distribution blocks installed in boxes shall be listed.
 Power distribution blocks installed on the line side of the service equipment
 shall be listed and marked "suitable for use on the line side of service equipment" or equivalent.
 
-### (2) Size.
+##### (2) Size.
 
 In addition to the overall size requirement in the first sentence of 314.28(A)(2),
 the power distribution block shall be installed in a box
 with dimensions not smaller than specified in the installation instructions
 of the power distribution block.
 
-### (3) Wire Bending Space.
+##### (3) Wire Bending Space.
 
 Wire bending space at the terminals of power distribution blocks
 shall comply with 312.6.
 
-### (4) Live Parts.
+##### (4) Live Parts.
 
 Power distribution blocks shall not have uninsulated live parts exposed within a box,
 whether or not the box cover is installed.
 
-### (5) Through Conductors.
+##### (5) Through Conductors.
 
 Where the pull or junction boxes are used for conductors
 that do not terminate on the power distribution block(s),
 the through conductors shall be arranged
 so the power distribution block terminals are unobstructed following installation.
+
+## Part III. Construction Specifications
+
+### 314.40 Metal Boxes, Conduit Bodies, and Fittings.
+
+<!-- TODO: TEXT OMITTED -->

nfpa-70_430_motors.md

@@ -0,0 +1,55 @@
+---
+id:
+aliases:
+  - nec-430
+tags:
+  - authorship/other
+  - destiny/uncertain
+  - status/incomplete
+  - topic/electrical
+  - type/encyclopedia
+---
+# Article 430 Motors, Motor Circuits, and Controllers
+
+## Part I. General
+
+### 430.1 Scope.
+
+This article covers motors,
+motor branch-circuit and feeder conductors and their protection,
+motor overload protection, motor control circuits,
+motor controllers, and motor control centers.
+
+<!-- TODO: TEXT OMITTED -->
+
+## Part II. Motor Circuit Conductors
+
+### 430.21 General.
+
+Part II specifies ampacities of conductors
+that are capable of carrying the motor current
+without overheating under the conditions specified.
+
+Part II shall not apply to motor circuits rated over 1000 volts, nominal.
+
+Informational Note:
+For over 1000 volts, nominal, see Part XI.
+
+Articles 250, 300, and 310 shall not apply
+to conductors that form an integral part of equipment,
+such as motors, motor controllers, motor control centers,
+or other factory-assembled control equipment.
+
+Informational Note:
+See 110.14(C) and 430.9(B) for equipment device terminal requirements.
+
+### 430.22 Single Motor.
+
+Conductors that supply a single motor
+used in a continuous duty application
+shall have an ampacity of not less than 125 percent
+of the motor full-load current rating,
+as determined by 430.6(A)(1),
+or not less than specified in 430.22(A) through (G).
+
+<!-- TODO: TEXT OMITTED -->

nfpa-70_450_transformers.md

@@ -0,0 +1,61 @@
+---
+id:
+aliases:
+  - nec-450
+tags:
+  - authorship/other
+  - destiny/uncertain
+  - status/incomplete
+  - topic/electrical
+  - type/encyclopedia
+---
+# Article 450 Transformers and Transformer Vaults (Including Secondary Ties)
+
+## Part I. General Provisions
+
+### 450.1 Scope.
+
+This article covers the installation of all transformers.
+
+Exception No. 1:
+Current transformers.
+
+Exception No. 2:
+Dry-type transformers
+that constitute a component part of other apparatus
+and comply with the requirements for such apparatus.
+
+Exception No. 3:
+Transformers that are an integral part
+of an X-ray, high-frequency, or electrostatic-coating apparatus.
+
+Exception No. 4:
+Transformers used with Class 2 and Class 3 circuits
+that comply with Article 725.
+
+Exception No. 5:
+Transformers for sign and outline lighting
+that comply with Article 600.
+
+Exception No. 6:
+Transformers for electric-discharge lighting
+that comply with Article 410.
+
+Exception No. 7:
+Transformers used for power-limited fire alarm circuits
+that comply with Part III of Article 760.
+
+Exception No. 8:
+Transformers used for research, development, or testing,
+where effective arrangements are provided
+to safeguard persons from contacting energized parts.
+
+This article covers the installation of transformers
+dedicated to supplying power to a fire pump installation
+as modified by Article 695.
+
+This article also covers the installation of transformers
+in hazardous (classified) locations
+as modified by Articles 501 through 504.
+
+<!-- TODO: TEXT OMITTED -->

stochastic-branch-takeoff.md

@@ -0,0 +1,24 @@
+---
+id:
+aliases: []
+tags:
+  - destiny/fleeting
+  - topic/electrical
+  - topic/estimating
+  - type/idea
+---
+# Stochastic Branch Takeoff
+
+generate a BOM from point loads distributed in a space.
+
+```yaml
+- x: 302.84
+  y: 2364.47
+  kW: 5.3
+  voltage: 277
+  phases: 1
+...
+```
+
+determine relative impact of factors
+* allowable voltage drop