Okay, let's address your request for 3/4" galvanized EMT conduit for underground burial in a 150' length. It's important to clarify some things and then provide the best recommendations.

Important Considerations & Clarifications



EMT is Generally NOT Approved for Direct Underground Burial

This is the biggest point.

EMT (Electrical Metallic Tubing), is thin-walled conduit and is generally NOT approved for direct burial in the ground according to the National Electrical Code (NEC). It's not designed to withstand the corrosion and physical stresses present underground. Even with galvanization, it will corrode over time. What you Should Use

For direct underground burial, you should be using

Rigid Metal Conduit (RMC), Rigid Nonmetallic Conduit (PVC Schedule 40 or 80), or Intermediate Metal Conduit (IMC). These are designed for direct burial. If using RMC or IMC, it still needs to be protected from corrosion in the soil, see below. NEC Guidelines

Always consult your local electrical codes and the NEC for the most accurate and up-to-date requirements. These codes will dictate what type of conduit is acceptable for underground burial in your area.

Corrosion Protection

Even with RMC or IMC, if the soil is corrosive, you may need to take extra precautions such as wrapping the conduit with a corrosion-resistant tape or coating.

Recommendations Based on Above

Assuming you MUST use metal conduit, I will give you some options to consider:1.

Best (Following Code): Rigid Metal Conduit (RMC)



Product

Look for 3/4" Rigid Metal Conduit (RMC) that is hot-dip galvanized. This will provide the best corrosion protection.

Where to Source



Home Depot, Lowe's, Menards

These big box stores usually carry 10' lengths of RMC. You'll need 15 sections plus couplings.

Electrical Supply Houses (e.g., Graybar, Rexel, City Electric Supply, Border States Electric)

These are the best places to get RMC. They will likely have it in stock and can offer better pricing, especially if you need multiple lengths. They will also have the proper couplings and fittings.

Important

To protect the RMC in the ground, you should coat it with a rust-preventative paint designed for underground use. Also, wrap the joints with a corrosion-resistant tape after assembly.2.

Intermediate Metal Conduit (IMC)



Product

IMC is lighter than RMC but still suitable for direct burial when properly protected. Look for 3/4" IMC that is galvanized.

Where to Source

Similar to RMC, check: Electrical Supply Houses (best option) Some Home Depot/Lowe's locations might carry it.

Important

As with RMC, protect the conduit with a coating and tape at the joints.3.

PVC Conduit (Schedule 40 or 80)



Product

Gray PVC conduit, not white (for plumbing).

Where to Source



Home Depot, Lowe's, Menards

These big box stores usually carry 10' lengths of PVC conduit. You'll need 15 sections plus couplings and PVC cement.

Electrical Supply Houses Important

PVC conduit is easy to work with. You will need to use PVC cement at the joints. Schedule 80 is physically more durable and is the best to use.

Where to Buy (General Advice)



Electrical Supply Houses

Always your best bet. They have knowledgeable staff who can help you select the right products and ensure you're meeting code requirements. They often offer better pricing than big box stores, especially on larger quantities.

Big Box Home Improvement Stores

Convenient, but be sure you know what you need and that it's appropriate for your application. Double-check the code requirements.

Important Safety Notes



Electricity is dangerous! If you're not comfortable working with electricity, hire a qualified electrician. Always disconnect power to the circuit you're working on before starting any electrical work. Follow all applicable codes and regulations.In summary:

I strongly recommend avoiding EMT for direct burial. Use RMC, IMC, or PVC conduit instead. Consult your local electrical codes, talk to an electrician if you're unsure, and source your materials from a reputable supplier. Don't cut corners on safety! Flag for review