According to CAN/ULC-S524, what is the design requirement for a Data Communication Link (DCL) serving more than one zone or floor area in terms of fault isolation?

Question: According to CAN/ULC-S524, what is the design requirement for a Data Communication Link (DCL) serving more than one zone or floor area in terms of fault isolation?

Answer options:

• It must be Class A
• It cannot use T-taps ✅ A single short circuit cannot disable more than one floor area or zone
• It must use at least 14 AWG wire

Correct answer: A single short circuit cannot disable more than one floor area or zone

Explanation: CAN/ULC-S524 §3.2.3.4 (under SLC requirements) specifies that if an isolator is used, it must be installed such that a single short-circuit fault does not prevent more than one floor area or zone from functioning. T-taps are allowed in Class B but impact fault isolation.