Hammond CT100A 100:5 Toroidal Current Transformer, 2 VA Burden

The CT100A is a 100:5 toroidal current transformer rated 2% accuracy at a 2 VA burden. It is suited to metering 100 A circuits in switchboards and control panels using a standard 5 A AC ammeter.

Construction is a toroidal design with 24" insulated secondary leads terminated in crimped ring connectors, and every model in the series has a two hole mounting bracket. It is suitable for use with a bare (uninsulated) primary conductor in circuits up to 600 V (4 KV Hi pot), or at higher voltages when a suitably insulated conductor is used. The series is listed under UL E227616 volume #1, file number X0DW2.

Overall dimensions for the CT100A are A 3.75 in (95 mm), B 1.35 in (34 mm), C 3.25 in (83 mm), D 3.00 in (76 mm), E 1.20 in (30 mm) and F 2.87 in (73 mm), with mounting slots G 0.22 in (6 mm) by H 0.37 in (9 mm). The listed shipping weight is 0.99 lbs (0.45 kg); the series table gives 1.1 lb. It is RoHS and REACH compliant.

To measure current, pass the wire carrying the current through the CT window so it acts as the primary winding, then connect the secondary to an ammeter with a 5 A movement. If a 100:5 ratio is needed at higher accuracy or burden, the series application data describes using a larger CT and looping turns: a CT400 with 4 primary turns gives 100:5 at 1.2% accuracy and 10 VA burden.