Hammond CT300A 300:5 Toroidal Current Transformer, 2-10 VA Burden

The CT300A is a 300:5 toroidal current transformer rated 0.6 - 1.2% accuracy across a 2 - 10 VA burden range. Built on the 4.75 in frame, it is aimed at metering 300 A feeders in switchgear and panels using a standard 5 A ammeter.

The unit is a toroidal current transformer fitted with a two hole mounting bracket and 24" insulated secondary leads with crimped ring connectors. A bare primary conductor may be used in circuits up to 600 V (4 KV Hi pot); at higher voltages, use a suitably insulated conductor. The series carries UL E227616 volume #1, file number X0DW2.

Overall dimensions for the CT300A are A 4.75 in (121 mm), B 1.35 in (34 mm), C 4.25 in (108 mm), D 4.00 in (102 mm), E 2.20 in (56 mm) and F 3.87 in (98 mm), with mounting slots G 0.22 in (6 mm) by H 0.37 in (9 mm). The listed shipping weight is 1.54 lbs (0.70 kg); the series table gives 1.8 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. A CT300A can also be used for a 100:5 or 150:5 requirement by looping the conductor 3 or 2 times through the window, following the series method of choosing a primary that is a multiple of the required rating.