Multimeter Test Leads: PVC vs. Silicone Wire Insulation

As mentioned in yesterday’s post about my Agilent 34461A multimeter purchase, I own quite a few multimeters. Multimeters, whether they cost $20 or $1200, require probes to measure voltage, current*, resistance, and other electrical properties, and probes are connected to multimeters using test leads.

*Except for clamp-on current meters.

Sometimes probes are permanently attached to test leads, other times test leads are modular so that different accessories can be connected to them.

When you buy a new multimeter, it will probably come bundled with test leads and possibly even a few attachments. There’s nothing wrong with using those test leads for basic measurements, but your needs might require you to purchase additional or different test leads separately or later on.

I have purchased a couple of test leads over the years, such as the very economical Extech TL809 kit (via Amazon) and Pomona 5901B straight-end kit (via Amazon).

Test leads are rated for different power levels and are available in different lengths, with different plug shapes, and with different insulating materials.

There are generally two types of test leads widely available – those with PVC insulation jacketing, and those with silicone insulation jacketing. At least one brand (Fluke) also offers heavy duty test leads with EPDM rubber insulation.

PVC vs. Silicone, What’s the Difference?

PVC-insulated test leads are often reasonably durable, flexible, and economically priced.

According to TestPath’s online catalog, PVC test lead wire costs about half as much as silicone test lead wire.

Additionally, PVC wire insulation typically contains phthalate plasticizers and lead-based compounds as stabilizers to improve its flexibility. Phthalates and lead both present potential health issues.

Silicone-insulated test leads are more flexible, more heat and burn resistant, more chemical and solvent resistant, and less sensitive to environmental temperatures.

Silicone-jacketed test leads are more expensive than those made with PVC insulation, and some users don’t like how it can make them feel sticky. The soft stickiness of silicone test leads also make them a little more prone to tangling.

Without question, I very strongly prefer silicone test leads over PVC leads, as I like the greater flexibility and softer touch of the wires and probe handles. Yes, silicone test leads cost appreciably more than PVC leads, but luckily test leads don’t need to be replaced too often.

If you ever want to replace your multimeter’s basic PVC test leads, here are a few inexpensive options:

Fluke TL71 Premium Leads with Built-in Probe (via Amazon)
Fluke TL224 SureGrip Test Leads (Modular probe not included) (via Amazon)
Probemaster 8000 Series Leads 8017S (via Probemaster)
Probemaster 9101 Starter Modular Leads (via Probemaster)

I have not yet used Probemaster or Fluke test leads, although Fluke does own Pomona, but both brands seem to be very well respected.