Threaded screw base guide

E17

Intermediate screw

E17 sits between candelabra E12 and standard E26. It is common in compact appliance fixtures where a full-size bulb would not fit.

Reviewed August 12, 2026
17 mm diameterNominal measurement · drawing not to scale
Connection
Threaded screw
Electrical context
Typically 120 V in U.S. fixtures
Also called
Intermediate base, Intermediate Edison screw, IES

How to identify E17

  1. Measure the threaded metal base across its widest point.
  2. Check the appliance label and owner's manual for wattage and heat requirements.
  3. Look for E17 or the words intermediate base.

Where it is commonly used

Microwave ovensRange hoodsOlder ceiling fansAppliances

Common use is a clue, not proof. The fixture label and model documentation take priority over a visual match.

Bulb shapes sold with this base

You may see these shapes with a E17 base. The base code does not guarantee the bulb width, length, beam angle, or clearance.

A15T7T8T10

Before you buy a replacement

  • An appliance bulb may need vibration or heat resistance.
  • A bulb that physically fits is not automatically appliance-rated.
  • Disconnect power before removing an appliance cover.