I’ve seen questions here similar to mine, but I just need to be sure about a few things before I proceed. I have to move the main load panel appx. four feet from its present location and I will be replacing the junk Federal Pacific (FP) unit with a new main breaker panel. The FP is inside, and connected to the meter via a short piece of rigid. Due to the way the FP is mounted flush to the framing and the way the ridged is configured, along with limited clearance for the drywall studs, running conduit from the meter to the new panel would be a nightmare, if not impossible to clearance issues. The current system is grounded via the panel connected to the meter box via the ridged. The meter box is then connected to the ground rod. Questions: 1- Can SEU be used from the meter to the panel as long as the SEU is sheathed and behind the wall? 2- Does the exposed (not behind the wall) short section of SEU into the panel have to be in conduit? 3- How would the system be grounded? Connect the SEU ground to the ground in the meter box?

tkrussell

SEU can be exposed , but will need to be protected if can be subjected to physical damage. The more it is protected the better.

Since your only going to have about 4-6 feet of SEU cable from the meter to the panel, the main panel can contain the Main Breaker, and the grounding can be done either at the panel or the meter.

shader

Quick follow up-forgot important item. What size wire to be used for a 100 amp panel? All the SEU I've seen is aluminum, ANy preference of aluminum vs. copper for SEU, if it is even available in copper?

tkrussell

For a residential 100 amp feeder, either #4 copper or #2 AL. I have not seen copper SEU cable for years, mostly because I don't do much residential, and I get mostly cheap customers. How I wish I had someone say "money is no object"!

Copper SEU cable is available, only from electrical distributors, and probably only special order. Be careful, any distributor may be subjected to a minimum order,if you want a small amount, the distributor will only sell you the entire amount .

See: SEU

Aluminum SE cable is much more common, just check to be sure Al is allowed in your area. The thing to be careful with Al wire is the connections, follow the manufacturers instructions, which is to wire brush the exposed metal, use anti- oxidant compound, and torque the mechanical connections to specifications.

Washington1

Clarify?

tkrussell

Sure, the connection of the grounding electrode system to the grounded conductor shall only be on the line side the the main service disconnecting means.

This connection may be at any one or more accessible locations, which is at the panel that contains the main breaker, the meter, and/or at the transformer.

So, consider a real situation that has a ground mounted transformer, a meter trim only (no disconnect in the meter), and a panel with the main breaker. You can actually drive 3 ground rods, one at each location.

Most meter trims, can, sockets, come with a #6 lug on the solid neutral bar , just for the purpose of allowing the connection of a grounding electrode. Typically, the utility transformer is pole mounted, the utility always grounds their poles/transformers, leaving the meter and panel as accessible locations for installers.

Grounding the neutral before the main switch is intended to create and/or insure the grounded conductor.

Washington1

.

It depends on the jurisdiction. This is why I ask for clarification. Not all areas will accept the Grounding connection in the meter can--rendering it non-accessible.

tkrussell

Correct, even thou it is allowed by the National Code, that is why my signature states to always check with local codes.

Washington1

Got it!

A protection clause!! <Joke>

tkrussell

I need something to rely on, I get a bit exhausted saying it over and over.

Got to be a little bit of attorney in this business, I am sure you know that, probably learned the hard way like I did.