#21PDU / RPP Power Distribution & Phase Balance Audit
Multi-Asset / Multi-Point Equipment Schedule
Inspect multiple transformers, panels, rooms, motors, or RCDs in this module without overwriting previous assets. Each item receives a permanent QR Sticker UID preserved across annual audits.
Sticker UID: OC-PDU0-5021Standard Limits, Equations & Space Presets
ANSI/TIA-942 and NEC 210.20(A) Data Center PDU / RPP distribution verification: 3-phase current imbalance, 80% continuous branch breaker loading rule, neutral ampacity, and UL 1561 K-factor.
Measured Inputs
Calculated / Evaluated Results
Imbalance = largest deviation from the average phase current / average x 100. Continuous branch loading is judged against the NEC 210.20(A) 80% rule for breakers that are not 100% rated.
Pending / Not tested — results stay neutral until valid measured values are entered.
- Pending
Average Phase Current & 3-Phase Load (at 400 V)
-
Calculated average phase current and equivalent 400 V 3-phase apparent power.
- Pending
Phase Current Imbalance
- %
Not tested - enter the measured value. Acceptance: Imbalance <= 10% across L1 / L2 / L3 (data centre commissioning target; up to 20% tolerated on lightly loaded panels) [Field convention / NEMA MG-1 formula]
- Pending
Continuous Branch Loading (80% Rule)
-
Not tested - enter the measured value. Acceptance: Continuous load (3 h or more) <= 80% of the device rating unless the assembly is 100% rated [NEC 210.20(A)]
- Pending
Neutral Loading
- %
Not tested - enter the measured value. Acceptance: Neutral current must stay within the neutral conductor ampacity; high triplen content can push it above phase current [NEC 220.61 / IEEE 1100]
- Pending
K-Factor Rating
-
Not tested - enter the measured value. Acceptance: K-13 or higher recommended for non-linear IT load [UL 1561 rating convention]
Verification Checklist (0 / 14)
1Floor PDU / Remote Power Panel (RPP) nameplate, upstream UPS source (Bus A / Bus B), and panelboard rating documented [ANSI/TIA-942]
2Branch Circuit Monitoring System (BCMS) CT accuracy verified within +/-1% against calibrated clamp meter
33-phase currents (L1, L2, L3) measured at main incomer and phase current imbalance verified <= 10% [NEMA MG-1]
4Dual-corded 2N A/B feed loading verified <= 40% per path so single-bus failover remains within the 80% continuous breaker limit
5Every continuous branch circuit (operating >= 3 h) verified <= 80% of breaker rating (unless 100%-rated assembly) [NEC 210.20(A)]
6Neutral conductor current verified <= 100% of neutral ampacity; double-sized (200%) neutral bar verified where triplen harmonics exist [NEC 220.61]
7PDU isolation transformer K-factor rating (>= K-13 for IT server loads) and winding temperature rise verified [UL 1561]
8Neutral busbar isolated from enclosure after single-point X0 bond, and Equipment Grounding (PE) bar bonded to data hall SRG
9Infrared thermography scan completed across all plug-in/bolt-on branch breakers, neutral terminations, and transformer taps
10Torque seal markings intact on main lugs, neutral bar, and branch circuit breaker load terminals
11Colour-coded A-feed (e.g., Red/Blue) and B-feed rack Whip / IEC 60309 commando sockets permanently labelled with RPP & circuit ID
12Laminated panel schedule inside RPP door matches actual live rack assignments with zero undocumented circuits
13DCIM / EPMS warning (70%) and critical (80%) branch circuit overload thresholds tested and active
14Minimum 1.0 m working clearance maintained in front of PDU/RPP doors with zero airflow or cable obstructions
General Notes
Free plan: 5 of 5 inspections / calculations left this month.