This first photo shows a level sensor junction box with a seal-off correctly placed between the junction box and the control panel to protect vital and expensive components inside the control panel from corrosive and explosive vapors.

The two seal-offs installed between the junction box and riser may protect the less costly junction box but will make it very difficult to remove the level sensors for servicing. If the sensors need to be removed, the leads will need to be cut below the seal-offs, new seal-offs and perhaps a length of conduit replaced. If the sensors still function their leads may now be too short.

In addition, and perhaps more importantly, these junction boxes may not be able to compensate for pressure or vacuum in the sump as intended, resulting in inaccurate level readings.

This second photo shows a motor lead junction box with a seal-off also correctly placed between the junction box and control panel. 

As was the case in the previous example, the additional seal-offs create issues when pulling the pumps for service. The motor leads will need to be cut, shortening lead lengths and creating additional work.

In summary, replacing cable runs between a junction box and control panel results in tremendous cost savings by comparison and further reinforces the value of breakout junction boxes.

**Seal-offs are effective only if the damming fiber and sealing compound are in place correctly. This is typically the responsibility of the electrician so be certain to check that this has been done.**