Regular CT Cons
Current transformers (CTs), sometimes also called current sensors, industry standard versions commonly have 5A as its output. They have the following disadvantages when used in branch circuits.
Regular CTs are large and will occupy a lot of space in a panel.
During retrofitting, the existing layout and wiring constrains any new additions, since regular CTs are large, it is often difficult if not impossible to fit them.
Why the Need?
Installing a CT w/o interrupting power
Split core CTs can be used, they can be installed easily w/o lengthy disruptions, reducing both time and effort.
Same circuit, but branching wiring
Small CTs allow for parallel connections.
A visual comparison of regular CTs with our dedicated CTs, both solid and split core.
Various CT Size Comparison
Existing Panel Retrofit
When an existing panel needs to be metered, CTs are absolutely required. But since space is cramped, regular CTs will not fit in between the wires, whereas dedicated CTs are small enough to fit.
Regular Split Body
|Outer Dimensions (W x H x D)||Window Dimensions (A x B)|
|114 x 145 x 32 mm||50 x 80 mm|
When doing temporary testing or when demands require that the power cannot be interrupted, then the regular split body type of CT is ideal. They are available with various capacities including 100A, 200A, 300A and 600A. They are all regular 5A output and can thus be used with any meter that accepts 5A as its CT input.
Regular Split Core
|Current Rating||Outer Dimensions
(W x H x D)
(A x B)
|100A / 200A||51 x 67 x 34 mm||24 x 24 mm|
|400A||68 x 85 x 42 mm||36 x 37 mm|
For existing panels that need to be retrofitted with meters, the space is sometimes simply too cramped to accommodate regular CTs due to their large size, but our regular split core CTs are only about half the size and can often fit within the space of existing panels; in addition, they can be installed without even having to interrupt the power or changing the wiring. Their output is 1A instead of 5A, they are available in 100A, 200A or 300A capacities.
Dedicated Solid Core
Our dedicated CTs are specific to our panel meters and the SMB350.
Regular CTs have poor accuracies and often need multiple windings to compensate, but our dedicated CTs are accurate enough that do not require it.
Dedicated Split Core
Sometimes it is necessary to meter an existing panel, but often the allowable space is too small for regular CTs, and to compound the problem, the power cannot be cut off even during installation. The solution is to use our dedicated split core CTs, not only are they about a third of the size and small enough to fit in existing panels, but they can be split open and simply snapped onto the wire during installation. Their accuracy is also very high compared to other split core CTs.
|Model #||Current Rating||Outer Dimensions
(W x H x D)
(A x B)
|CT-5S||5A||25 x 41 x 33 mm||10 mm|
|CT-50S||50A||26 x 48 x 23 mm||10 mm|
|CT-100S||100A||31 x 54 x 30 mm||16 mm|
|CT-200S||200A||36 x 76 x 45 mm||24 mm|
|CT-400S||400A||60 x 80 x 40 mm||35 mm|
|CT-600S||600A||60 x 80 x 40 mm||35 mm|
|CT-50SB||50A||23 x 39 x 26 mm||10 x 10 mm|
|CT-100SB||100A||32 x 56 x 31 mm||16 x 16 mm|
|CT-200SB||200A||51 x 67 x 34 mm||24 x 24 mm|