Okay, let's break this down and figure out the severity of the situation and potential solutions.

Understanding the Problem

You're being asked to power a 100A-rated guard booth panel from a 60A panel (LP-1). You currently only have wiring in place suitable for the actual running load of the individual branch circuits within the guard booth, not for a full 100A feed. You suspect, rightly so, that the 60A panel isn't capable of handling a 100A sub-panel.

Yes, you very likely have a significant problem.

Here's why:1. Overloading the 60A Panel

If you try to feed a 100A panel from a 60A panel, you risk overloading the 60A panel's main breaker and potentially the feeder conductors supplying the 60A panel. This can lead to nuisance tripping, overheating of the conductors, and a potential fire hazard.2.

NEC Requirements

The National Electrical Code (NEC) dictates that the feeder to a subpanel must be sized to handle the anticipated load of that subpanel, and the feeder must be protected by an overcurrent device (breaker) no larger than the ampacity of the feeder conductors. You can't simply slap a 100A breaker on the 60A panel and call it a day.3.

Panel Rating vs. Load

A 100A panel is RATED for 100A. That doesn't necessarily mean you'll actually draw 100A. However, the wiring and the breaker feeding the panel MUST be rated to support the panel's capacity and any future expansion within that panel.4.

Guard Booth Load

The entire guard booth is only running 7.9A but NEC requires that the panel is rated for 100A because it allows for future loads in the guard booth.

Immediate Actions and Considerations1. STOP

Do not attempt to connect the guard booth panel to the 60A panel with the existing wiring. This is a dangerous situation.2.

Assess the Actual Load

You mentioned the 7.9A FLA. That's helpful, but you need a complete load calculation for the guard booth. Include: Lighting (total wattage) Heaters (if any - wattage) Air Conditioner (FLA, LRA, and voltage) Outlets (how many, and what's likely to be plugged in - assume at least 1.5A per outlet) Any other equipment.3.

Consult a Qualified Electrician

This is not a DIY situation. A licensed electrician can perform a proper load calculation, determine the correct feeder size, and ensure the installation meets all applicable codes.4.

Check Existing Panel Capacity

Can LP-1 handle an additional load.

Possible Solutions (depending on load and existing infrastructure) Run a New Feeder

This is the most likely solution. Run a new, appropriately sized feeder (conductors and conduit) from a source that can handle the 100A demand (or whatever the load calculation dictates) to the guard booth panel. This may involve a new breaker in the main panel, running conduit, pulling wire, and terminating the connections.

Reduce the Guard Booth Panel Size

If the actual load calculation for the guard booth is significantly less than 100A, and if the inspector and engineer approve, you might be able to use a smaller panel (e.g., a 60A panel) and a smaller feeder. This is a less likely solution, as the 100A panel was likely specified for a reason (future expansion, etc.). Reducing the panel size will likely require a change order and approval.

Load Shedding (Less Likely)

If the load is very intermittent, you might explore load shedding strategies. This involves using controls to ensure that certain loads are automatically disconnected when other, higher-priority loads are running. This requires careful design and is rarely a simple solution.

In summary, you need to have a licensed electrician evaluate the situation, perform a proper load calculation, and determine the correct and code-compliant solution. Ignoring this problem could lead to serious consequences. Flag for review