Okay, let's break this down and address your questions about installing a Type 1 SPD (Surge Protective Device) in your 12-meter EZ Meterpak system.

Analysis of Your Situation Fused Disconnect

You have a 400A fused disconnect serving as the main for your meter bank. This is a good location to install the SPD.

EZ Meterpak Configuration

The fact that each meter only has space for a 2-pole breaker is the limiting factor. This means you can't easily just add a breaker for the SPD at each meter location.

Bus Bar Access

You've identified the main bus bars within the fused disconnect as a potential attachment point.

Legality and Safety of Attaching Lugs to Bus Bars NEC (National Electrical Code) Considerations



NEC 110.3(B) - Installation and Use

This is the most important code reference. Equipment must be installed according to the manufacturer's instructions and listings. You cannot simply drill and tap busbars. That voids the listing and is a massive code violation.

NEC 408.3(A) - Connection to Busbars

This section dictates how connections to busbars must be made. It typically requires listed and labeled methods.

Manufacturer's Instructions

This is critical. The only way to know if attaching lugs directly to the bus bars is permissible is if the manufacturer of the disconnect specifically allows it and provides instructions and hardware for doing so. Consult the documentation of your disconnect.

Listing and Labeling

Any method you use to connect to the busbars must be listed and labeled for that purpose. This means the lugs, the method of attachment (e.g., specific bolts and torque values), and the overall installation must meet the requirements of a recognized testing laboratory (like UL).

Therefore, unless the manufacturer of your fused disconnect specifically allows for lug connections to the busbars and provides instructions and listed hardware for doing so, it is almost certainly a violation of the NEC to directly attach lugs to the busbars.Alternative SPD Installation Methods (If Direct Bus Bar Connection Isn't Allowed)

If direct bus bar connection is not possible (which is highly likely), here are the most common and code-compliant alternatives:1. SPD with Dedicated Disconnect/Breaker



Install a separate, small fused disconnect or breaker enclosure adjacent to your main 400A disconnect. Feed this disconnect from the load side of your main disconnect (tapping off the conductors that feed the meter bank). This gives you a dedicated, protected circuit for the SPD. You can then land the SPD wires on the terminals of the disconnect or breaker. Advantages: Clean, safe, and easily serviceable. Provides overcurrent protection for the SPD. Disadvantages: Requires additional physical space.2. SPD with Inline Fuses

Some SPDs are designed to be installed in line with the feeders. You would run the conductors from the load side of your main disconnect, through the SPD (which includes fuses), and then to the meter bank. Advantages: More compact than a dedicated disconnect. Disadvantages: Can be more difficult to service the fuses. Requires careful selection of an SPD designed for this type of installation.3.

Load Side of Main Breaker or Disconnect

This is usually the most straightforward. If there is available space in the load side of the main breaker or disconnect (the line feeding the meter bank), you can tap off of that and run that to a dedicated disconnect for the SPD.

SPD Selection Recommendations

Here are some considerations for choosing an SPD: Type 1 vs. Type 2



Type 1

Designed for installation before the main overcurrent protective device (OCPD) – meaning at the service entrance. These are designed to withstand higher surge currents. Since you are installing this at the main disconnect, a Type 1 is appropriate.

Type 2

Designed for installation after the main OCPD – at branch panels or downstream locations.

SCCR (Short Circuit Current Rating)

The SPD's SCCR must be equal to or greater than the available fault current at the point of installation. Your electrician should calculate the available fault current at the service entrance.

Voltage Rating (MCOV - Maximum Continuous Operating Voltage)

Make sure the SPD's voltage rating matches your system voltage (e.g., 120/240V single-phase, 208Y/120V three-phase, 480Y/277V three-phase). The MCOV should be slightly higher than the nominal voltage.

Surge Current Capacity (kA)

This indicates how much surge current the SPD can handle. Higher is generally better. For a main service entrance, look for SPDs with a surge current capacity of at least 80kA per mode (L-N, L-G, N-G). 100kA or more is even better for robust protection.

UL 1449 Listing

Ensure the SPD is listed to UL 1449, the standard for surge protective devices.

NEMA Rating

Consider the environment. If the disconnect is outdoors, choose an SPD with a NEMA 4X enclosure (weatherproof).

Recommended SPD Brands

These are some reputable brands that offer high-quality SPDs: Eaton/Cutler-Hammer Square D/Schneider Electric Siemens Leviton Littelfuse Midwest Electric ProductsExample SPD Models Eaton CHSPT2ULTRA

Type 1, high surge current capacity, UL listed.

Square D HEPD80

Type 1, good value.

Siemens FS140

Type 1, robust.

Crucial Steps1. Consult the Fused Disconnect Manufacturer's Documentation

This is the most important step. Determine if direct bus bar connections are permitted. If not, explore the alternative methods.2.

Calculate Available Fault Current

Your electrician needs to calculate the available fault current at the service entrance.3.

Select an SPD

Choose an SPD that meets the requirements outlined above (Type 1, appropriate voltage, SCCR, surge current capacity, UL listing).4.

Hire a Qualified Electrician

Ensure the installation is performed by a licensed and experienced electrician who is familiar with the NEC and local codes.5.

Permit and Inspection

Obtain the necessary permits and have the installation inspected by the local electrical inspector.

In summary, while the idea of attaching lugs directly to the bus bars might seem like the easiest solution, it is almost certainly not permissible without specific authorization and instructions from the disconnect manufacturer. Explore the alternative methods and choose an SPD that provides adequate protection for your electrical system. Flag for review