Meaning of PD2 Marking on Current Transformers

Issue

Customers question the meaning and implications of the PD2 marking found on CT labels, such as the “PD2” indication shown on some Schneider Electric split‑core and solid‑core CT models.

Product

Current Transformers (CTs), including but not limited to:

• Split‑core CTs (e.g., METSECTSP series)
• Solid‑core CTs used with Schneider Electric energy meters and monitoring equipment

Environment

Electrical distribution systems where CTs are installed in:

• Indoor electrical panels
• Industrial or commercial facilities
• Enclosures with normal environmental conditions (non‑corrosive, non‑conductive dust)

Cause

The PD2 marking refers to Pollution Degree 2, a classification defined by IEC/UL insulation standards. This marking indicates the expected level of environmental contamination around the equipment.

According to IEC 60664‑1 and UL 61010 standards, Pollution Degree 2 means:

• Only non‑conductive contamination is normally present.
• Temporary conductivity may occur only due to condensation.

Resolution

The PD2 marking It simply informs users that the CT is designed and safety‑rated for installation in environments meeting Pollution Degree 2 conditions.

Recommended actions:

1. Verify installation environment: Ensure the CT is mounted inside an enclosure or panel that meets PD2 environmental characteristics.
2. Avoid excessive dust, humidity, or corrosive atmospheres: If the environment exceeds PD2 (e.g., heavy industrial dust, chemical vapors, persistent moisture), consider additional enclosure protection or relocating equipment.
3. No technical intervention is required unless the CT is being installed in a harsher‑than‑rated environment.

Example:

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