When you're sorting through industrial power supplies transformers for a control cabinet, the first question is not which unit is "better" but what voltage your field devices expect. The MEAN WELL MDR-100-12 and the NDR-120-24 are both DIN rail power supplies, but they serve different DC output levels and installation conditions. If you're replacing an existing unit, match the voltage first; if you're designing a fresh cabinet, let the field devices dictate the DC level. Here's how to choose.
Quick Verdict
Choose the MEAN WELL MDR-100-12 for 12V panels and the NDR-120-24 for 24V applications. The two units are not direct substitutes, so your system voltage is the deciding factor.
Comparison Table
| Product | Output | Current | Price | Installation Area |
|---|---|---|---|---|
| MEAN WELL MDR-100-12 | 12V | 7.5A | $29.99 | Indoor |
| NDR-120-24 | 24V | 5A | $44.99 | Indoor/Outdoor |
Where Each Product Wins
- MEAN WELL MDR-100-12 wins when your control circuit is 12V. The adjustable-voltage feature, LED indicator, and DC OK signal give you output tuning and status feedback from the unit itself.
- NDR-120-24 wins when your control circuit is 24V. The DIN rail mount and 5A output align it with many 24V industrial controls.
Product Notes
MEAN WELL MDR-100-12 (12V DIN Rail Power Supply)
This unit supplies 12V at 7.5A with a 90W rating, which makes it a reasonable match for a small control panel filled with 12V relays, indicators, and controllers. The housing is enclosed, and the unit is meant for indoor installation. The adjustable-voltage feature is handy when you need to fine-tune the output, and the LED indicator plus DC OK signal give you immediate visual confirmation that the supply is active. The listed dimensions, 100mm depth and 90mm height, keep the footprint compact for a tight cabinet. If your application is a 12V system in a dry, protected cabinet, this is the easier of the two to fit into that role. Its main limitation is that it is a 12V supply only, so it cannot power 24V devices, and the indoor-only installation area means you should keep it out of wet or exterior locations.
NDR-120-24 (24V DIN Rail Power Supply)
The NDR-120-24 is built around the 24V output that many industrial controls use. It is listed at 5A and mounts on a DIN rail, with an indoor/outdoor installation area that gives it more flexibility in where it can be placed. If your control cabinet sits in an unheated shed, a covered outdoor area, or any environment where moisture can be a concern, the indoor/outdoor rating is the key reason to pick this one. The blue housing is a minor visual distinction but not a functional advantage. The trade-off is that this is a 24V unit, so a 12V circuit would require the MEAN WELL MDR-100-12 instead. Choose the NDR when the voltage and the environment both point toward 24V and outdoor tolerance.
Final Choice by Use Case
If your decision is still a tug-of-war, let voltage settle it. For a 12V control panel, the MEAN WELL MDR-100-12 is the right choice because it adds adjustable output and status feedback. For a 24V industrial application, the NDR-120-24 is the supply to order. Keep the installation area in mind-indoor-only versus indoor/outdoor-when you make the final call.
