45. MOV for 120VAC Appliance Surge Protection

1. Component Purpose

This is the same concept as the 230VAC MOV, but sized for the US 120VAC market. The MOV sits across the AC input after the fuse and clamps voltage surges to protect the appliance’s power supply and electronics.

For 120VAC mains, the standard MOV rating is 150VAC maximum continuous. This provides headroom above 120V nominal (which peaks at ~170V) while still giving effective clamping.

Required: 150VAC · ≥4.5kA surge · ≥50J · 1-Circuit · Disc · Through Hole · Littelfuse · RoHS

Through-Hole-disc-MOV

2. How to Find It on DigiKey

Go to DigiKey.com → Circuit Protection → Varistors, MOVs

Apply these filters:

  • Maximum AC Volts → 150V
  • Current - Surge → 4.5kA or higher
  • Energy → 50J or higher
  • Number of Circuits → 1
  • Mounting Type → Through Hole
  • Package / Case → Disc
  • Manufacturer → Littelfuse Inc.
  • Part Status → Active

Tip:  For consumer appliances, UL/CSA safety certification often requires the MOV to be in series with a fuse. The fuse disconnects the degraded MOV before it reaches thermal runaway.

3. Key Specifications & What They Mean

SpecificationRequiredWhy
Max AC Volts150VStandard for 120VAC US mains.
Surge Current≥4.5kAAdequate for consumer/appliance use.
Energy≥50JHandles repeated consumer mains surges.
Circuits1Single line-to-neutral protection.
PackageDisc, Through HoleStandard MOV form.
ManufacturerLittelfuseCompany AVL requirement.
Temp Range−40°C to +85°CStandard operating range.
RoHSYesCompliance required.

4. Selecting a Safe, Production-Ready Part

The filtered list will show matching parts. Before you pick one, check: Is it Active? Is stock available? Is the manufacturer reputable? Is a datasheet available?

Full checklist: How to Select a Safe, Production-Ready Component — EWskills Guide

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