Residential Service — Voltage Monitoring Report

Generated 2026-09-23 09:27:06 · Continuous monitoring since 2026-06-29 20:49:29 · 7,041,164 samples recorded

Measurement Method

Three calibrated energy meters, each on a separate 120 V branch circuit, spanning both legs (Leg A and Leg B) of the split-phase service.
One 240 V line reference measuring line-to-line voltage and grid frequency.
Sampled continuously every 1–2 seconds since 2026-06-29 20:49:29.
Legs measured independently; Leg A + Leg B cross-checks against the 240 V line reference.

Worst Recorded Measurements

Largest simultaneous 120 V split: Leg A 101.2 V and Leg B 123.1 V simultaneously — a 21.9 V difference — on 2026-08-23 16:31:31

Lowest 240 V service reading: 220.2 V (2026-07-02 22:34:32). This is a measured line-to-line drop, not a diagnosis of its cause.

Key Findings (measured)

Voltage-split events (≥3 V)2108

Major splits (≥8 V)78

Lowest single-leg voltage101.2 V (2026-08-23 16:31:29)

Highest single-leg voltage130.1 V (2026-07-24 12:36:39)

240 V line range220.2–247.6 V (nominal 240)

Grid frequency range59.748–60.066 Hz (normal)

What the Data Shows

The recurring major pattern is a sharp drop on one 120 V leg while the other leg remains comparatively stable.
During the deepest recorded episodes, the 240 V line-to-line reference also drops. That is not the classic opposite-leg / stable-240 V signature.
Grid frequency remained near 60 Hz during the recorded voltage changes.
The daily and hourly tables show when the measured pattern occurred so a utility or electrician can compare it with load and service conditions.

Interpretation note: labels in this report describe simultaneous meter patterns only. They are intended to help the utility or electrician diagnose the issue; they do not assert a confirmed component or physical cause.

Daily Largest Voltage Split

Date	Largest simultaneous A/B difference
2026-06-29	4.8 V
2026-06-30	14.0 V
2026-07-01	11.7 V
2026-07-02	16.8 V
2026-07-03	17.6 V
2026-07-04	5.2 V
2026-07-05	15.9 V
2026-07-08	3.4 V
2026-07-10	4.8 V
2026-07-11	4.4 V
2026-07-12	8.4 V
2026-07-13	7.9 V
2026-07-14	7.2 V
2026-07-15	6.4 V
2026-07-16	5.6 V
2026-07-17	6.2 V
2026-07-18	3.5 V
2026-07-19	3.7 V
2026-07-20	7.4 V
2026-07-21	6.8 V
2026-07-22	4.9 V
2026-07-23	21.1 V
2026-07-24	17.9 V
2026-07-25	8.5 V
2026-07-26	6.4 V
2026-07-27	5.3 V
2026-07-28	3.6 V
2026-07-29	6.4 V
2026-07-30	6.1 V
2026-07-31	6.1 V
2026-08-01	5.6 V
2026-08-02	17.5 V
2026-08-03	4.3 V
2026-08-04	5.4 V
2026-08-05	5.7 V
2026-08-06	3.8 V
2026-08-07	4.5 V
2026-08-08	5.1 V
2026-08-09	7.0 V
2026-08-10	7.5 V
2026-08-11	5.1 V
2026-08-12	6.5 V
2026-08-13	4.0 V
2026-08-14	18.0 V
2026-08-15	20.1 V
2026-08-16	19.0 V
2026-08-17	18.1 V
2026-08-18	6.3 V
2026-08-19	6.6 V
2026-08-20	5.4 V
2026-08-21	18.8 V
2026-08-22	11.0 V
2026-08-23	21.9 V
2026-08-24	7.1 V
2026-08-25	5.8 V
2026-08-26	6.8 V
2026-08-27	5.3 V
2026-08-28	5.7 V
2026-08-29	5.2 V
2026-08-30	5.1 V
2026-08-31	3.5 V
2026-09-01	6.9 V
2026-09-02	5.0 V
2026-09-03	5.5 V
2026-09-05	3.2 V
2026-09-06	3.3 V
2026-09-07	3.2 V
2026-09-08	3.2 V
2026-09-09	3.2 V
2026-09-10	3.1 V
2026-09-12	3.3 V
2026-09-13	3.6 V
2026-09-14	3.1 V
2026-09-16	5.4 V
2026-09-17	5.9 V
2026-09-18	5.6 V
2026-09-19	5.7 V
2026-09-20	5.5 V
2026-09-21	5.2 V
2026-09-22	5.4 V
2026-09-23	3.8 V

Timing — Events by Hour of Day

00:00	65
01:00	4
02:00	3
03:00	2
04:00	15
05:00	5
06:00	3
07:00	7
08:00	47
09:00	44
10:00	37
11:00	28
12:00	35
13:00	23
14:00	68
15:00	86
16:00	238
17:00	178
18:00	105
19:00	242
20:00	193
21:00	267
22:00	352
23:00	61

Recorded Major Events (≥8 V split)

Timestamp	Leg A	Leg B	Imbalance	Low leg	240V line
2026-08-23 16:31:31	101.2 V	123.1 V	21.9 V	Leg A	221.8 V
2026-08-23 15:24:40	106.0 V	121.4 V	15.5 V	Leg A	231.1 V
2026-08-23 15:04:34	106.3 V	121.5 V	15.2 V	Leg A	228.8 V
2026-08-23 07:34:13	108.0 V	122.3 V	14.2 V	Leg A	226.9 V
2026-08-23 02:20:23	106.7 V	122.5 V	15.9 V	Leg A	225.5 V
2026-08-23 01:52:44	107.0 V	121.3 V	14.3 V	Leg A	231.9 V
2026-08-22 23:02:00	108.6 V	119.6 V	11.0 V	Leg A	231.1 V
2026-08-22 21:41:20	107.7 V	117.2 V	9.5 V	Leg A	228.2 V
2026-08-21 19:51:42	106.0 V	122.1 V	16.2 V	Leg A	226.8 V
2026-08-21 19:50:57	114.0 V	122.2 V	8.2 V	Leg A	236.8 V
2026-08-21 17:19:51	104.9 V	123.0 V	18.1 V	Leg A	226.0 V
2026-08-21 16:51:39	107.6 V	121.2 V	13.5 V	Leg A	226.4 V
2026-08-21 16:29:10	104.0 V	118.7 V	14.7 V	Leg A	222.5 V
2026-08-21 10:14:46	104.5 V	123.3 V	18.8 V	Leg A	225.9 V
2026-08-17 11:32:46	105.0 V	123.1 V	18.1 V	Leg A	224.5 V
2026-08-17 11:32:11	105.8 V	123.1 V	17.4 V	Leg A	228.0 V
2026-08-17 10:09:14	106.7 V	123.2 V	16.5 V	Leg A	239.4 V
2026-08-17 09:29:05	108.9 V	122.1 V	13.2 V	Leg A	235.4 V
2026-08-16 21:43:31	106.3 V	122.4 V	16.1 V	Leg A	227.0 V
2026-08-16 17:02:51	106.9 V	120.7 V	13.8 V	Leg A	226.9 V
2026-08-16 16:58:16	106.5 V	121.6 V	15.2 V	Leg A	225.8 V
2026-08-16 16:08:17	108.6 V	123.1 V	14.6 V	Leg A	233.3 V
2026-08-16 15:17:49	108.6 V	122.2 V	13.6 V	Leg A	237.7 V
2026-08-16 10:51:51	105.5 V	124.5 V	19.0 V	Leg A	225.5 V
2026-08-15 18:02:43	102.5 V	122.6 V	20.1 V	Leg A	226.5 V
2026-08-15 11:03:05	106.6 V	123.5 V	16.8 V	Leg A	226.9 V
2026-08-15 11:01:43	108.4 V	123.4 V	15.1 V	Leg A	229.4 V
2026-08-14 18:14:16	106.3 V	121.2 V	15.0 V	Leg A	235.5 V
2026-08-14 18:01:24	106.4 V	122.0 V	15.6 V	Leg A	224.0 V
2026-08-14 17:23:49	104.3 V	122.4 V	18.0 V	Leg A	225.5 V
2026-08-14 17:22:53	106.7 V	122.5 V	15.7 V	Leg A	225.2 V
2026-08-02 18:08:38	105.5 V	122.1 V	16.6 V	Leg A	224.4 V
2026-08-02 17:46:30	107.3 V	120.3 V	12.9 V	Leg A	225.7 V
2026-08-02 17:24:39	106.1 V	122.6 V	16.5 V	Leg A	227.1 V
2026-08-02 09:34:30	105.1 V	122.6 V	17.5 V	Leg A	232.1 V
2026-08-02 08:52:17	111.4 V	122.1 V	10.7 V	Leg A	236.9 V
2026-08-02 08:14:16	106.8 V	121.1 V	14.3 V	Leg A	235.2 V
2026-08-02 01:21:33	114.2 V	122.3 V	8.1 V	Leg A	238.9 V
2026-07-25 07:15:33	113.0 V	121.5 V	8.5 V	Leg A	236.6 V
2026-07-24 19:44:07	111.5 V	119.6 V	8.1 V	Leg A	234.8 V

Measured at the point of use with RMS metering sampled at 1–2 second intervals. The report presents observations for professional diagnosis and intentionally avoids assigning a cause from voltage pattern alone.