The Square D(TM) Main lugs loadcentres typically are used as an add-on load center and is connected to the service entrance loadcentre when spaces for more circuits are needed or when the main disconnect is located elsewhere. It does not contain the main breaker. This sub-panel has plug-on neutrals which allow the use of plug-in (no pigtail) Square D (CAFI) Combination Arc Fault breakers. CAFI breakers connect the breaker directly to the neutral bar, allowing for faster installations and easier troubleshooting. CSA approved for vertical, horizontal or inverted mounting. This product is backed by a limited lifetime warranty.