CCTD-20

A 20 amp Class CC time delay fuse rated 600 volts alternating current and 300 volts direct current, supplied five to a pack. Class CC is the compact branch circuit fuse used across motor starters, control transformers and machine panels, and the time delay characteristic is what lets it sit through a starting current it would otherwise clear on.

Why the time delay characteristic is the whole point

A motor or a control transformer draws a large current for a fraction of a second when it energises. A fast acting fuse of the same rating sees that as a fault and opens, which is why panels protected with the wrong characteristic blow fuses on startup and nothing is ever found wrong. A time delay fuse is built to ride through that inrush and still clear a genuine short quickly. The two look nearly identical, fit the same holder and cost about the same, so the characteristic has to be specified rather than assumed.

Specifications

Best for: anyone maintaining motor starters, machine panels and control transformer primaries that already use Class CC holders, and shops that would rather hold spares than wait on a courier.

Common questions

What is the difference between a time delay and a fast acting Class CC fuse?
A time delay fuse rides through the brief inrush of a motor or transformer instead of clearing on it, while a fast acting fuse of the same rating would open. Both fit the same holder, which is exactly why they get mixed up.

Can I use it on a direct current circuit?
Within the published figures, yes. The catalogue rates it for direct current as well as alternating current, with a lower interrupting capacity on the direct current side, so check your available fault current against that number.

How big a motor will it protect?
The supplier catalogue describes the series as intended for motor circuits up to forty horsepower, but the fuse size for any given motor comes from the motor nameplate and the Code, not from the fuse family.

Why does it come five to a pack?
Class CC is a three phase habit. Most installations use three at a time, so a five pack covers one set plus two spares, which is the quantity most panels end up needing.