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Some lights brighten while others dim.

A licensed electrician should take the readings, and the utility handles its side of the service.

Customers put it like this

  • some lights got really bright
  • half the house is dim and half is bright
  • the lights go bright when the dryer runs
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Stop first if

  • Lights are swinging bright and dim now.Keep sensitive gear off if that can be done without risk. Call the utility and a licensed electrician now.
  • Equipment is smoking or there is a burning odor.Leave the area and call emergency services.
01

Ask on the call

5

Homeowner? These are the questions a good technician will ask you. Having the answers ready makes the first visit count.

  1. Which lights go bright and which go dim?
  2. What is running when it happens?
  3. Is this a house or a unit in a multi-unit building?
  4. Has anyone worked near the service or meter lately?
  5. Has anything been damaged, or does anything smell hot?
02

Bring

4
  • Rated multimeter
  • True-RMS clamp meter
  • Flashlight
  • Phone for photos
03

Check on site

5
  1. Note the pattern. It points toward an open or high-resistance neutral.
  2. At a reachable 240 V point, a qualified person records each leg to neutral, plus line-to-line.
  3. Note unequal legs that shift with load. Line-to-line can look normal during this.
  4. Record the building type. Multi-unit 120/208 service is normal there and does not point toward a utility fault.
  5. Check 240 V appliances, chargers and inverters for a 208 V rating and matching profile.
04

Keep on the record

4
  • Each leg to neutral plus line-to-line, with the load at the time
  • Building type and service voltage
  • Damaged equipment list
  • Utility contact notes

General guidance for a qualified person, not a finding about any home. The person on site decides.