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40 votes

What type of cable should I bury for a small utility shed?

Why bury a cable when you can be future-proof? The primary issue with direct buried cables is that you have to dig them up in order to upgrade them, a costly proposition. Hence, it's a far better ...
ThreePhaseEel's user avatar
35 votes
Accepted

GFI outlets tripped after power outage

Some brands of GFCI’s trip on power loss. I first found this when putting them in on a bathroom sink outlet that was switched. Every time the light switch was turned off the GFCI tripped when the ...
Ed Beal's user avatar
  • 103k
30 votes

subpanel breaker tripped as well as main breaker - should I be concerned?

Grats on your successful generator test :) Whenever you have a bolted fault, you flow hundreds of amps. The only thing that impedes flow is the resistance of the wires themselves, which you can look ...
Harper - Reinstate Monica's user avatar
30 votes
Accepted

Why are all the neutral wires in a sub panel burnt or melted?

Because NEC 110.14(D) wasn't followed. A torque wrench was not used to set the screw torques. This is why the rule was added to NEC 2014. Now if the work predates 2014, it was legal and should not ...
Harper - Reinstate Monica's user avatar
26 votes

I do not have power to all my breakers

Oh dear. This is a foogly mess. First, you did the right thing by punching that main panel breaker down onto a single. The problem is with the subpanel; it is very badly misconfigured by a guy who ...
Harper - Reinstate Monica's user avatar
25 votes

What type of cable should I bury for a small utility shed?

I'm going to be a bit contrarian and say 10/3 UF. It's pricier and overkill for your existing setup, but here's why it could be worth doing it now. A single 12/2 means you only get 20 amps at your ...
Machavity's user avatar
  • 24.9k
20 votes
Accepted

What are the pros/cons for aluminum vs copper wiring on feeders?

For feeders, aluminum is perfectly acceptable. It got a bad rap when it was used for residential circuits back in the 70s where it might not have been terminated as carefully as it should have. But ...
Milwrdfan's user avatar
  • 4,759
18 votes
Accepted

Are the grounds and neutrals in this electrical subpanel reversed?

Whoever wired this panel simply was not paying attention The installer who wired this panel did not pay attention to the schematic on the label, assuming that removing the bonding strap was enough ...
ThreePhaseEel's user avatar
17 votes
Accepted

Can I install two 60 amp EV chargers on a 100 amp subpanel?

I'm going to focus on the modern way to do this, since it's so very correct that I'd almost call other ways wrong. The newest EVSEs provide for that. Use them. I.E. don't make the thing harder than it ...
Harper - Reinstate Monica's user avatar
17 votes

What are the pros/cons for aluminum vs copper wiring on feeders?

Aluminum and copper are equally acceptable as far as code. There are exceptions, largely for historical reasons, in some jurisdictions - anything from "no aluminum for 15A/20A circuits" to &...
manassehkatz-Moving 2 Codidact's user avatar
17 votes
Accepted

Adding EV Charger (100A) in secondary panel (100A) fed off main (200A)

It's astounding what is possible. EV charging tech is smarter than you could imagine. "Don't I need 100A though?" TLDR: No. The Ford Connected Charge Station Pro can work on any breaker from ...
Harper - Reinstate Monica's user avatar
15 votes

Federal Pacific 200a main panel problem with oversized 100a 2pole breaker

The 100A breaker is overcrowding the other slots for a reason: to enforce stab limits. Even a stopped clock is right twice a day, and FPE got that right. If you did what you wanted to, you would ...
Harper - Reinstate Monica's user avatar
15 votes

GFI outlets tripped after power outage

Ed's advice is correct. For a time, some builders of GFCI devices considered this behavior to be a "feature". Undocumented, of course. This is largely gone from the market, so I would cautiously ...
Harper - Reinstate Monica's user avatar
15 votes
Accepted

How to use a 100 amp sub panel for a 50 amp input

Just wire it up. There is no problem using a sub panel that can take more current than you will ever feed it. Points to note: The cable to your hot tub will be rated for 50A (not 100A); therefore ...
Martin Bonner supports Monica's user avatar
15 votes

Are there safety concerns or code violations with my garage sub-panel?

It is bad, more than a few violations here if I understand what is being fed. First violation no clamps /bushings coming into the panel 2 places. Next a 40 amp breaker feeding #12 possibly 14 awg wire ...
Ed Beal's user avatar
  • 103k
15 votes

Can I use a 125A panel with a breaker and wiring sized for 90A?

I'm going to venture to guess that your inspector is conflating a service with your feeder. A service is the connection from the house to the utility supply. Normally there is no over-current ...
Greg Hill's user avatar
  • 30.8k
15 votes
Accepted

Is this subpanel installation up to code?

TLDR: Looks great. The only thing I'm not a fan of is the 100A breaker being directly opposite another large 240V breaker. I understand the temptation to crowd the biggest breakers near the main so ...
Harper - Reinstate Monica's user avatar
15 votes
Accepted

Hot Tub GFCI Breaker continously trips at sub-panel

You appear to have connected the Neutral wire to the ground lug at the disconnect. That makes a ground fault. Connect the ground wire to the ground lug, and connect the neutral wires only to each ...
Ecnerwal's user avatar
  • 217k
14 votes
Accepted

Using an Ohm Meter to test for bonding of a subpanel

The panel looks beautiful, except for one problem. You are 100% correct. Because neutral and ground are bonded in the main panel (whether that is a regular big panel or a small panel/disconnect at the ...
manassehkatz-Moving 2 Codidact's user avatar
13 votes

Can I connect a 100A subpanel to a 100A main panel?

Let me try and answer some of your questions. First the panels you are looking at that are rated 100A simply means you can use them for any application up to 100A. You can for example add a 60A ...
Retired Master Electrician's user avatar
13 votes

Considering doing a 100A sub panel install on my own. Any guidance would be much appreciated

I can tell you right now that that liquidtight is too small for what you want to do The AC installer likely ran either 1/2 or 3/4" for the LFMC, depending on the size of the circuit. That's going to ...
ThreePhaseEel's user avatar
13 votes
Accepted

Running electrical to a shed

Generically I'd knee-jerk to conduit and 30A 240V service with a sub-panel, but if your needs are going to be adequately met by 20A 120V power and the loading is sufficiently low that the voltage drop ...
Ecnerwal's user avatar
  • 217k
13 votes

Sub panel install issue

I'd be seriously tempted to email that picture to the licensing board... I assume from your question that this was installed, incorrectly, by licensed electricians. Buy a ground bar to fit your panel, ...
Ecnerwal's user avatar
  • 217k
13 votes

Old service entry cable left inside former main service panel

You can't do copper-aluminum splices with blue wire nuts. You will need to get Polaris connectors which are rated for the size of aluminum wire and also the #12 jumpers. (or a double stepdown, e.g. ...
Harper - Reinstate Monica's user avatar
12 votes

Separating Ground and Neutrals in Mainpanel before installing sub panel

The grounds and neutrals do not have to be separated in the main panel if it is, in fact, the main panel. Sometimes there's confusion if you have a main disconnect/breaker outside by the meter. In ...
JACK's user avatar
  • 81.7k
11 votes

Can I connect a 100A subpanel to a 100A main panel?

If your panel is full, you'll likely want to have the service evaluated, to determine if it's still large enough to meet your needs. It's possible that you may want to upgrade to a larger service, ...
Tester101's user avatar
  • 132k
11 votes

How to use a 100 amp sub panel for a 50 amp input

It's a rating. Like tires. Go shopping for tires. Almost any tire these days is rated 112 mph. *You're allowed to drive 65 on those, it is saying don't exceed 112 mph*. It's the same with ...
Harper - Reinstate Monica's user avatar
11 votes

Running electrical to a shed

In the USA you get to play fast and loose with this. If you simply extend with 12 AWG, you'll have 0.6% voltage drop per amp that you draw... so a 1/4 amp battery charger won't give any drop at all, ...
Harper - Reinstate Monica's user avatar
10 votes
Accepted

Adding a new "knockout" to side of main electrical panel

Go out the bottom, otherwise the hole or any flaw in the conduit will bring water, rust and failure into your box. Use two conduit bodies to make your 180 degree turn. You can do this pretty tight ...
Harper - Reinstate Monica's user avatar
10 votes

Considering doing a 100A sub panel install on my own. Any guidance would be much appreciated

This is a "walk in the park" with enough knowledge, but what you've said reveals some gaps. Also an EE degree can do more harm than good, because it encourages you to overthink or "outsmart" the NFPA....
Harper - Reinstate Monica's user avatar

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