# Extech MA640 True RMS AC/DC Clamp Meter with NCV vs Southwire 21050T / 21550T 400A True RMS AC/DC Clamp Meter: specs and price compared

A sourced, side-by-side comparison of the Extech MA640 True RMS AC/DC Clamp Meter with NCV (Extech (Teledyne FLIR)) and Southwire 21050T / 21550T 400A True RMS AC/DC Clamp Meter (Southwire) among clamp meters.

## Side by side

| Spec | Extech MA640 True RMS AC/DC Clamp Meter with NCV | Southwire 21050T / 21550T 400A True RMS AC/DC Clamp Meter |
| --- | --- | --- |
| US price | not published | not published |
| Brand | Extech (Teledyne FLIR) | Southwire |
| Ac current range | 60.00 A / 600.0 A | 400 A |
| Dc current range | 60.00 A / 600.0 A | 400 A (per user-facing marketing copy and verified purchaser reviews on southwire.com describing DC clamp-amp use; exact numeric DC accuracy table not published on the fetched product page) |
| Jaw opening | 1.5 in (40 mm), conductors up to 500 MCM | — |
| Ac dc voltage range | AC 6.000V/60.00V/600.0V; DC 600.0mV/6.000V/60.00V/600.0V | — |
| True rms | Yes | Yes |
| Resistance continuity | 600.0Ω to 60.00MΩ, with continuity | — |
| Capacitance | 40.00nF to 4000µF | Yes |
| Temperature | -4°F to 1400°F (-20°C to 760°C), Type K | Yes |
| Cat safety rating | CAT III 600V | CAT III 600V |
| Display count | 6000 | — |

## Key differences

- Ac current range: Extech MA640 True RMS AC/DC Clamp Meter with NCV 60.00 A / 600.0 A vs Southwire 21050T / 21550T 400A True RMS AC/DC Clamp Meter 400 A
- Dc current range: Extech MA640 True RMS AC/DC Clamp Meter with NCV 60.00 A / 600.0 A vs Southwire 21050T / 21550T 400A True RMS AC/DC Clamp Meter 400 A (per user-facing marketing copy and verified purchaser reviews on southwire.com describing DC clamp-amp use; exact numeric DC accuracy table not published on the fetched product page)
- Capacitance: Extech MA640 True RMS AC/DC Clamp Meter with NCV 40.00nF to 4000µF vs Southwire 21050T / 21550T 400A True RMS AC/DC Clamp Meter Yes
- Temperature: Extech MA640 True RMS AC/DC Clamp Meter with NCV -4°F to 1400°F (-20°C to 760°C), Type K vs Southwire 21050T / 21550T 400A True RMS AC/DC Clamp Meter Yes

## Sources

- Extech MA640 True RMS AC/DC Clamp Meter with NCV: https://www.flir.com/products/ma640?vertical=condition+monitoring&segment=solutions (flir.com, verified 2026-08-05)
- Southwire 21050T / 21550T 400A True RMS AC/DC Clamp Meter: https://www.southwire.com/tools-equipment/test-measurement/21550t-clamp-meter-400a-ac-dc/p/65031840 (southwire.com, verified 2026-08-05)

Canonical: https://frontdeskreview.com/gear/clamp-meters/extech-ma640-vs-southwire-21050t/
Cite: Per The Front Desk Review, Extech MA640 True RMS AC/DC Clamp Meter with NCV (not published) vs Southwire 21050T / 21550T 400A True RMS AC/DC Clamp Meter (not published) — sourced spec-by-spec comparison at https://frontdeskreview.com/gear/clamp-meters/extech-ma640-vs-southwire-21050t/
License: CC BY 4.0.