The MTT MS3720C is a plug-in CT transmitter built for clamp-type current transformers, letting it read current ranges from as low as 5A up to 600A depending on the clamp used. Because it works with a clamp-on CT rather than a wired-in transformer, it is well suited to retrofit installations and panels where the current-carrying conductor already exists and adding a wired CT would mean shutting the circuit down.
Like the rest of the plug-in transmitter series, the MS3720C calculates the true RMS value of the AC current and converts it into a standard DC output, with a second isolated output available for feeding an independent monitoring or alarm system. It clips into its own plug-in socket base for fast swap-out during calibration or maintenance, and flexible AC or DC power plus wall or DIN rail mounting make it easy to fit into an existing panel.
| Input Range | 0-5A to 0-600A AC, clamp-type CT (per ordering code) |
| Output | 0-20mA or 4-20mA DC current; 10mV to 20V DC voltage; single or dual isolated output |
| Accuracy | Better than ±0.4% of span (10%+ input) |
| Temperature Effect | ±0.2% of span per 10°C change |
| Response Time | 450ms max. (0-90%, step input at 100%) |
| Isolation | 4-way isolation between input, output 1, output 2, and power |
| Dielectric Strength | 2000V AC |
| Power Supply | 100-240V AC, 24V DC, or 100-240V DC |
| Dimensions | W29 × H86 × D125mm |
| Weight | 120g max. (main unit), plus 80g max. socket |
| Mounting | Wall or DIN rail mounting |
| Terminals | M3.5 screw terminals |
| Operating Temperature | -5 to 55°C |
| Operating Humidity | 5 to 90% RH, non-condensing |
Frequently Asked Questions
What is the MTT MS3720C used for?
It’s a CT transmitter built for clamp-type current transformers. It reads the current picked up by a clamp-on CT and converts it into a standard DC signal, making it a good fit for retrofit installations where you don’t want to open the circuit to fit a wired-in CT.
What current ranges does the MS3720C support?
It covers ranges from 5A up to 600A depending on the clamp CT used and the ordering code specified. Tell us the clamp CT’s rated current and we can confirm the matching ordering code.
What’s the difference between the MS3720C and the standard MS3720?
The standard MS3720 is built for a wired-in 1A or 5A secondary CT. The MS3720C is built for a clamp-on CT and covers a much wider primary current range (5A to 600A), making it the right choice when you want to add current monitoring without opening up the circuit.
Can the MS3720C provide two separate outputs?
Yes — a second isolated output is available, so the current reading can feed a controller and a separate monitoring or alarm system at the same time.
How do I know which ordering code I need?
Send us the clamp-on CT’s rated current and the output signal your receiving equipment expects, and we can confirm the right ordering code before you order.
Download MTT MS3720C Slim Plug-In CT Transmitter information here
Spec Sheet: SpecSheet1_MS3720C_Rev130_E.pdf
Manual: Manual1_MS3720C_Rev120_E.pdf
