Independent comparisons. We may earn from shop links. More info

How to use a multimeter

Updated: October 2026

You have a meter and a dead part on the bench: a battery, a pulled fuse, or a lead you already know is isolated. How to use a multimeter here is the jacks and the function before the probes touch anything. The same meter is the wrong tool for deciding that a mains circuit is dead. This page walks through DC voltage and a dead continuity check, then stops. The full set is the [multimeter comparison](/hub/measuring-equipment/multimeter). Peter F. set these steps from GS38, HSG85 and Electrical Safety First on 17 October 2026. Not a laboratory test. A qualifying purchase can earn us a commission at no extra cost to you.

You have a meter and a dead part on the bench: a battery, a pulled fuse, or a lead you already know is isolated. How to use a multimeter here is the jacks and the function before the probes touch anything.

Our top picks

VENLAB VENLAB VM-600M

Best overall

VENLAB VENLAB VM-600M
9.4/10about £26.99
View offer
TESMEN TESMEN TM-510

Preis-Tipp

TESMEN TESMEN TM-510
9.2/10about £16.99
View offer
ULTRICS ULTRICS UT0021YB

Alternative

ULTRICS ULTRICS UT0021YB
9.0/10about £7.99
View offer
On this page
  1. 1.Leads and function before the probes touch anything
  2. 2.DC volts on a battery or a low-voltage lead
  3. 3.Continuity only on a dead part
  4. 4.Where a multimeter stops

Leads and function before the probes touch anything

Put the black lead in COM. Put the red lead in the volts and ohms socket, often marked VΩ, for voltage, resistance or continuity. The amp socket is a different hole. The red lead goes there only when you intend to measure current. Leave it in the amp jack and then touch a voltage, and the meter tries to pass that voltage through the current shunt. GS38 says current connections are made with the apparatus dead. The TESMEN TM-510 does not list a current range. The ULTRICS UT0021YB states a 10 A input for a maximum of 10 seconds. The Aicevoos AS-118D still needs the red lead in the 10 A socket for current. Missing ranges are on the multimeter buying guide.

DC volts on a battery or a low-voltage lead

Select DC volts on a range above the voltage you expect. Haynes uses the 20 V DC range for a 12 V car battery. Black probe to negative, red to positive. A minus sign means the probes are reversed. You do not need to disconnect a car battery to read the posts. Read the number, then stop. The RAC and Haynes bands stay on the multimeter car battery page. On the dial, a solid line and a dashed line mean DC, and a wave means AC. If the meter is on AC by mistake, a DC battery can show nothing useful.
VENLAB VENLAB VM-600M

Testsieger

VENLAB VENLAB VM-600M
9.4/10about £26.99
View offer

Continuity only on a dead part

Fluke's UK continuity note puts the black lead in COM, the red lead in the volts and ohms jack, and the circuit de-energised. A beep means a path. It does not mean the part is good in every other way. A fuse you have pulled is the right example: one probe on each metal end. A beep supports a continuous wire. Silence supports an open fuse. A fuse still in a live holder is the wrong example. GS38 allows continuity with the apparatus dead, not across a live circuit. If you cannot see that the part is unplugged, do not guess. A quiet non-contact sensor does not mean the conductor is dead.

Where a multimeter stops

GS38 says use a test lamp or a two-pole detector, proved on a known live source before and after, to decide whether voltage is present or absent. HSG85 does not recommend multimeters or volt sticks for proving dead. This page does not contain that procedure. A new circuit, a replacement consumer unit, or work in a bath or shower room is notifiable in England under Part P. Stop if you cannot prove dead with a proper detector, if a lead is damaged, or if the job is notifiable. Regulation 16 of the Electricity at Work Regulations 1989 requires competence where knowledge is needed to prevent danger. A screen number does not certify BS 7671. Distorted AC is a buying choice on the true RMS multimeter page.

Common questions

Where do the red and black leads go?
The black lead stays in COM. For voltage, resistance and continuity, the red lead goes in the volts and ohms jack. It goes in the amp jack only for a current measurement, and only on a meter that lists a current range. The TESMEN TM-510 does not list current. On the ULTRICS, the 10 A input is stated for 10 seconds. Look at the red plug before every test.
How do I measure DC volts on a battery?
Select DC volts on a range above the battery voltage. Haynes uses the 20 V DC range for a 12 V car battery. Black goes to negative, red to positive. A minus sign means the probes are swapped. You can read the posts without disconnecting the battery. What the number means for a rested car battery is on the car-battery page.
How do I continuity-test a fuse that is unplugged?
Take the fuse out so it is a dead part on the bench. Black lead in COM, red lead in the volts and ohms jack, meter on continuity. Touch one probe to each end. A beep means a path through the fuse. No beep means it is open. Leave a fuse that is still in a live holder alone.
Can I use NCV silence to say a cable is dead?
No. A non-contact voltage function that stays quiet is not proof that a cable is dead. HSG85 does not recommend volt sticks for proving dead, and GS38 wants a test lamp or two-pole detector, proved before and after. One UK buyer in this set also found a pen meter's cable sensing was AC only. Treat NCV as a rough alert, never as the decision that mains is safe to touch.
What happens if the red lead stays in the amp jack?
You can put the meter across a voltage while it is wired as an ammeter. That routes the source through the current shunt and can blow the fuse, damage the meter, or worse. Before a voltage or continuity check, the red lead is in the volts and ohms jack. On the Aicevoos AS-118D, current still needs that 10 A socket. Finish the current job, then move the lead back.
When do I stop and call an electrician?
Stop if the circuit might be live and you cannot prove it dead with a proper voltage detector, if the leads are damaged, or if the work is notifiable in England under Part P, such as a new circuit, a consumer-unit change, or work in a bath or shower room. The Electricity at Work Regulations 1989 require competence for work where knowledge is needed to prevent danger. A hobby DC check on a battery you can hold is a different job.

Related pages

Best multimeter

Multimeter

Multimeter buying guide: the job, then CAT and True RMS

Multimeter car battery: rested 12.6 V, not cranking

True RMS multimeter: when the AC wave is not a sine

Sources

Public UK sources from the research digest for this comparison: HSE, legislation.gov.uk, Martindale, Megger, Fluke, Electrical Safety First, the RAC and GOV.UK. Listing prices, star lines and review themes are the stored amazon.co.uk figures for these ASINs, not a fresh page view. Updated 17 October 2026.

  1. HSE GS38, electrical test equipment for electricians (retrieved 17 October 2026)
  2. Electricity at Work Regulations 1989, regulation 16 (retrieved 17 October 2026)
  3. Martindale, how to choose a multimeter (retrieved 17 October 2026)
  4. Megger, measurement category (retrieved 17 October 2026)
  5. Fluke, what is true-RMS (retrieved 17 October 2026)
  6. Electrical Safety First, Best Practice Guide 2 (retrieved 17 October 2026)
  7. RAC, car battery voltage (retrieved 17 October 2026)
  8. GOV.UK, Approved Document P (retrieved 17 October 2026)