Yes, MC4 connectors are waterproof. They have an IP67 waterproof and dustproof electrical rating. Once connected together, this rating means they are able to work for at least 30 minutes while under upto 1 meter of water. Adding to this, they are 100% protected against solid objects including sand and dust.
You should understand that MC4 connectors are only waterproof when the male and female ends are snapped together.
When a single connector is left unconnected, they are not waterproof. In this scenario, the internal connection is open to the elements which allow water and dirt to get inside. This is a particular problem in marine/saltwater conditions where corrosion occurs quickly.
To protect an exposed MC4 connector you should consider one of the following:
- Long term: Adding MC4 protector caps on unused connections.
- Short term: Apply standard electrical tape over the connector.
- Position the connector away from direct weather exposure (E.g. point downwards so water drains away).
- Create a drip loop so water flows down the wire and away from the connection.
It is standard electrical practice to always cover exposed connections to avoid damage, dirt, and accidents!
If you do leave an MC4 connector exposed for a short period you might not have any problems. Even a small amount of water won’t cause immediate damage, just ensure it is dry before connecting it up.
Are MC4 Connectors Waterproof Summary
I hope the information above answers your question about whether MC4 connectors are waterproof.
Solar panels are designed to be left outside in all conditions including rain and snow. This means the connectors, cables, and junction boxes are also able to deal with these adverse conditions once installed.
You should be careful during installation when you have exposed wires and connections. Certainly, avoid working in the rain. If you have to leave connections until you acquire another component, then make sure to cover the exposed areas with caps or tape. In addition, place it away from direct exposure to water and dirt.
