Fuse holders and fuse blocks are part of the protection system. Their clips, terminals, insulation, touch-safe construction and rejection features determine whether the assembly can carry rated current and withstand a fault. Cross-referencing by the phrase '10 x 38 holder' alone is especially risky because UL Class CC and midget fuses share a similar envelope but differ in rejection and listing.

Common holder families and model examples

Class CC vs midget: the most common error

Bussmann CHCC1DU is a one-pole modular Class CC holder used with KTK-R, LP-CC and FNQ-R families. CHM1DU is a one-pole midget holder. CHCC2DU and CHM2DU are two-pole variants; the extra pole changes width, busbar selection and wiring layout. The suffix 'I' in many holder families indicates an open-fuse indicator, but indicator voltage limits must be checked.

Model selection checklist

1. Identify the exact fuse class and series, not only its approximate dimensions.

2. Choose a holder voltage and current rating equal to or higher than the circuit and installed fuse requirements.

3. Match pole count: CHCC1DU is 1 pole, CHCC2DU is 2 pole and CHCC3DU is 3 pole.

4. Confirm mounting: 35 mm DIN rail, panel/screw mount, PCB mount, in-line or fused disconnect.

5. Check conductor material, wire range, terminal type, tightening torque and whether one or two conductors are permitted per terminal.

6. Confirm SCCR or short-circuit withstand with the selected fuse and the equipment assembly.

7. Review touch-safe/IP20 requirements, open-fuse indication, neutral poles, comb-busbar and accessory compatibility.

8. Check spacing, heat dissipation and derating when multiple poles or holders are grouped in an enclosure.

9. Verify UL/CSA/IEC approvals and the equipment's listing before substituting a different holder manufacturer or model.

Worked replacement examples

Frequently Asked Questions

Can a Class CC fuse go in a midget holder?

Do not assume it can or should. Class CC relies on rejection geometry and a Class CC holder/listing. Use a holder specifically identified for Class CC.

What is the difference between CHCC1DU and CHCC1DIU?

Both are one-pole Class CC modular holders; the DIU version includes indication. Confirm the indicator's operating-voltage range for the application.

Can USGCC1 replace CHCC1DU?

It is a same-purpose candidate, not a blind direct replacement. Compare dimensions, terminal range, ratings, indication, busbar/accessories, SCCR and panel certification.

Does a 30 A holder require a 30 A fuse?

No. A holder rated 30 A can generally accept lower-rated compatible fuses within its identified family. The fuse rating is selected from the protected circuit and equipment requirements.

Bottom line

Cross-reference the holder as an engineered component. Start with fuse class, then voltage/current/SCCR, pole count, mounting and terminals. Model pairs such as CHCC1DU vs CHM1DU look similar in a catalog but serve different fuse categories.

For a holder replacement, send ASBEAM the installed holder model, fuse model, pole count, line/load wire sizes, system voltage and panel photo. This prevents a physically plausible but non-compliant swap.

Technical references

• Eaton - CHCC1DU official product data

• Eaton - CHM1DU official product data

• Mersen - USGCC and USGM holder datasheet

Littelfuse - L600C Class CC fuse blocks