SPD surge protector shows a fault indicator – when should it be replaced

What the indicator means

Many SPDs have a window or status indicator. If it shows a fault, the protective element has likely exhausted its capacity.

What to check

• The status indicator.
• The upstream fuse or protection.
• The grounding connection.

When to replace

If the manufacturer indicates that the module has failed, it must be replaced.

Important

An SPD without proper grounding cannot function effectively.