Size marking on the case is the bare core dimension (OD × ID × H), not the cased or finished size.
Nanocrystalline toroidal core 20×12×8 mm
20×12×8 mm nanocrystalline toroidal core, Blue PBT Class B 130C.
CCNT-020-012-008-MFBL is a 20×12×8 mm nanocrystalline toroidal core for small CTs, gate-drive transformers, and auxiliary power transformers. Its 12 mm inner diameter supports practical secondary windings, while high-permeability nanocrystalline material helps achieve useful magnetizing inductance at low turns. Choose this size when winding window, magnetic area, and envelope must stay in balance for the target current or VA.
Former part number: CC-NC-CMC-001-20
In stock
$10.53Pack of 5
$2.11 per piece
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Volume pricing
Online packs are $10.00 minimum. Buy packs totaling under 50 pieces. 50+ is quoted.
| Pack / qty | Unit price | How to buy |
|---|---|---|
| Pack of 5 | $2.11 | Buy online |
| Pack of 10 | $1.87 | Buy online |
| Pack of 25 | $1.56 | Buy online |
| 50+ pieces | Quoted | Request quote |
Technical Specifications
Bare core dimensions
Cased / finished dimensions
Magnetic properties
Finish and handling
Environmental
Product photos
Applications and selection
Applications
- small CTs
- gate-drive transformers
- auxiliary power transformers
- ground-fault sensing cores
- low/medium-current protection and metering CTs
- gate-drive isolation transformers
- ground-fault/residual-current sensing transformers
- auxiliary bias power transformers
When to choose this size
This 20×12×8 mm toroidal core is sized for small CTs and related designs in the nearby size family. Step down to the 16×10×6 mm core when board space, enclosure height, or a tighter footprint matters more than winding room. Move up to the 25×16×10 mm core when you need a larger outer diameter, winding window, or higher throughput than this part can comfortably support. In short, pick CCNT-020-012-008-MFBL when your design for small CTs fits this window and OD; pick a neighbor when compactness or power handling shifts the trade-off.
Winding notes
Magnetic calculations should use the bare 20×12×8 mm geometry (Ae 0.269 cm², Le 5.02 cm). The winding must fit the finished window: cased ID is 10.6 mm, not the 12 mm bare ID. Keep the winding distributed around the toroid to limit leakage and local heating. High permeability (μi 80,000) supports useful magnetizing inductance at practical turn counts; stay within 1.25 Tesla saturation and the -40°C to +130°C PBT Class B 130C limit.
Related application guides
Frequently asked questions
Are stated dimensions bare or cased?
The 20×12×8 mm size marked on the case is the bare core (OD × ID × H). Finished cased size is 22.6 × 10.6 × 10 mm. Use bare dimensions with Ae and Le for magnetic design, and the finished inner diameter for winding clearance.
Is this core suitable for a current transformer?
Yes. It is a nanocrystalline core sized for small CTs, including low/medium-current protection and metering CTs. High permeability helps you reach useful secondary inductance with practical turns in a 20 mm OD.
When should I choose a different size instead?
Choose the 25×16×10 mm core when you need more winding window, heavier wire, or higher throughput. Choose the 16×10×6 mm core when board space or a smaller footprint matters more than this 20×12×8 mm envelope.
Need this core for your application?
Get pricing, availability, and winding support for CCNT-020-012-008-MFBL.