10A fused jack
The 10A jack is the input for currents up to 10 amps, and FUSED means a fuse inside the meter protects it. A separate mA or µA jack, also fused, takes small currents.
Easily confused with
How to read it
Fluke’s guide describes the A jack as the red lead’s input for current up to 10 A, and the mA/µA jack for 0 µA to 400 mA; Fluke’s 115 and 117 print 10 A FUSED beside their current jack. Fluke’s application note on meter safety shows a meter marked 400mA FUSED and 10A MAX FUSED.
The fuses differ by meter. Klein’s MM400 has 500 mA and 10 A fuses rated 600 V, Extech’s EX330 500 mA and 10 A fast-blow fuses rated 250 V, and Mastech’s MAS838 a 200 mA fuse rated 250 V.
Also searched as: 10A max fused, 10A on a multimeter, 400mA fused, A jack, fused input, mA jack.
These pages describe what each setting, marking and reading means. They are not instructions for measuring anything. Meters differ between makers and models: the meter’s own manual says what each of its symbols means, which measurements it is rated for, and how to use it safely.
Why the current jacks are fused
A current jack has a very low resistance. Fluke’s application note explains that with the leads in it and across a voltage source it becomes a short circuit, whatever the dial is set to, and calls the fuses the only thing standing between an inconvenience, a blown fuse, and a potential disaster. The note says to use only the high-energy fuses the maker specifies, rated for voltage and short-circuit interrupting capacity. The volts and ohms jacks have a high input impedance and need no fuse; they have overvoltage protection instead.
Time limits at high current
Fluke’s 115 and 117 allow 10 to 20 A for 30 seconds, then 10 minutes off; Extech’s EX330 allows 10 A for 30 seconds at most every 15 minutes; Klein recommends 30 seconds followed by 10 minutes of recovery above 6 A.
Look-alikes
The COM jack takes the black lead for every measurement and has no fuse marking.
Read next
- Next in Multimeter symbolsCAT II, CAT III and CAT IV ratingsCAT II, CAT III and CAT IV are measurement categories from the safety standard IEC 61010-1. The number says how close to the power source the meter is built to withstand voltage spikes, and the voltage beside it is the working voltage for that category.
- The same shape in AI labels and iconsAI iconAI-generated or AI-changed content. A badge with the letters AI, often in a circle or beside a word such as generated or modified, labels an image, video, sound or text as made or altered with artificial intelligence. The European Union publishes an official set of these icons.
More multimeter symbols
The same shape elsewhere
Browse symbols drawn with circles or letters and numbers.
Sources
- Multimeter Symbols, Buttons, Dials, and Display, Fluke learning centre article, Fluke Corporation, Digital multimeter jacks
- 114, 115, and 117 True-rms Multimeters: Users Manual, PN 2572573, July 2006, Rev. 1, 2/07, Fluke Corporation (copy hosted by UCL Electronic and Electrical Engineering), Terminals; Rotary switch positions
- ABCs of multimeter safety, Application note, Fluke Digital Library, Fluke Corporation (copy hosted by RS Components), Meter illustration; Fuses and overload protection
- MM400 Auto-Ranging Digital Multimeter: Instruction Manual, MM400 instruction manual, Klein Tools (copy hosted by UBC Earth, Ocean and Atmospheric Sciences), Electrical specifications; Operating instructions, AC/DC current
- Mini Multimeter with Non-Contact Voltage Detector, Model EX330: User’s Guide, EX330-EU-ENG V4.2 1/08, Extech Instruments (copy hosted by Core Electronics), Safety instructions; General specifications
- MAS838 Digital Multimeter: Operator’s Instruction Manual, MAS838 manual, Mastech (copy hosted by Akizuki Denshi), Specifications
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research
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