Installing Level 2 at Home (SOOW vs. NM-B) Which one?

2 principles:

In the service panel, the neutral terminal bar and the ground terminal bar may be identical. Better practice would be to keep them separate, but they are connected there anyway, so it's fine if neutrals and grounds are intermixed on the same terminal bar. In all downstream panels (subpanels), the neutral bar must be kept insulated from the enclosure (to which the ground bar is bonded), and you can't mix neutral and grounds on the same bar.

When terminating the EGCs (grounds), if the panel label says you can put two grounds in a single terminal hole, that's allowed (typically only for small sizes like #12 and #14). But it's never allowed to double up neutral conductors in one hole, or to put a neutral and a ground in the same hole.

Cheers, Wayne

^What he said.

And in case you're still wondering, with 6/3 you need 2 separate holes. If you're out of holes, you can double up 2 12 or 14 AWG wires to make room. Personally, I'd buy an 'extender' bus or a longer ground bus that adds more spaces but either way is fine and just doubling up a few existing wires would be quicker.

In case you're wondering, the service panel is the enclosure that has the main service disconnect for your house. If you don't have sub-panels in your house, it's the (one and only) 'breaker box'.

And if you do disconnect any existing neutral or ground wires to make room or move things around, be sure to turn the breaker off for those circuits before doing so. Sorry if that is stating the obvious but it is important.

Better yet, turn off the main and have a flash light handy before doing any work inside the panel. Be safe.

If you regularly work at your breaker or fuse box(es) then it's a good idea to mount a battery operated swivel work light near each of them, so you have full illumination with the panel off. I'll post a link to the one I use. The only quirk is that it has no mounting holes. It has a very strong set of magnets, so you instead mount a piece of flat steel (steel brackets or strips of galvanized steel work fine) where you want the light. That also makes it portable, but I suggest you leave it there permanently. Any good light of this type will work, but I've had the following one mounted by the main panel for years and it still works fine on the original batteries.

https://smile.amazon.com/gp/product/B08P2FTRTF/ref=ppx_yo_dt_b_asin_title_o08_s01?ie=UTF8&psc=1




This one is also great: https://smile.amazon.com/gp/product/B08P2LDVSY/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1



For some reason only the enlarged images would link.

Thank you everyone!

Will use two separate hole. 1 separate empty one for neutral and as for the ground - can I double it up with the other grounds on the main bus? There is another bus in the back with a bit more empty holes. I assume they are connected (I just cannot see it due to the amount of cables), 2nd option would be connect the neutral to the main bus and the ground to the 2nd bus, is that common/ correct way to bond too?

pr0lab said:

can I double it up with the other grounds on the main bus?

Click to expand...

This was answered already. Your panel should have a label on it that says something like "grounding terminal bar--small holes--#14 through #6 or (2) #12 or (2) #14" where I made up the numbers and the wording may be a bit different. That label would not permit 1 #12 and 1 #14 in the same hole on the grounding terminal bar. I expect the ground in your 6/3 UF is large enough that it will require its own hole.

More broadly:

(1) The panel you are working in, can you flip a breaker outside the panel to kill all grid power entering the panel? In that case it is a subpanel (that breaker or one upstream from it would be your service disconnect), and the neutral bar should be isolated from the case, with neutrals and EGCs on separate terminal bars.

(2) Or is the upstream most breaker located in this panel? In that case it's the service panel, and you need to be extremely careful working in the panel. As even when the main breaker is open, the service entrance conductors on the line side are energized and can kill you. Modern service panels provide an additional barrier over the line side lugs on the main breaker, but if yours is more than a few years old, those terminations may be exposed.

Regardless, you need to safely visualize all the terminal bars and understand how they are connected (or isolated). The term bus is generally reserved for the ungrounded busses at the back of the panel that the breakers connect to (although the neutral terminal bar may be referred to as a neutral bus, particularly in the newer "plug-on neutral" panels).

BTW, what is your 40 amp EVSE model, and why did you select 6/3 UF?

Cheers, Wayne

Thank you, Wayne. It is a service panel and it is a few years old. I don't have another disconnect above the panel (cables go right outside).

for the EVSE I am thinking of either something simple (w/o wifi) like this https://www.amazon.com/gp/product/B08B7WQHPZ/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 or more of a station like this https://www.amazon.com/dp/B08H2LYFH...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

The reason for selecting 6/3 UF was not to deal with conduit and not needing to have 2 separate cables as some of my cable runs outside (under the deck). Also it looks like the trend for the future it for more power hungry vehicles so I decided to install it once to support other cars in the future if needed (w/o having to redo)

Unless price is a strong concern, I'd go with a Clipper Creek basic charging station. Made in the US, 3 year warranty for consumer use, rugged and reliable. The plastic mounting tabs, if they still use them, are a bit small but do the job. The Canadian made Grizzle - e or whatever the exact spelling is, is also very good. Neither is as pricey as the "smart" stations.

wwhitney said:

More broadly:

(1) The panel you are working in, can you flip a breaker outside the panel to kill all grid power entering the panel? In that case it is a subpanel (that breaker or one upstream from it would be your service disconnect), and the neutral bar should be isolated from the case, with neutrals and EGCs on separate terminal bars.

(2) Or is the upstream most breaker located in this panel? In that case it's the service panel, and you need to be extremely careful working in the panel. As even when the main breaker is open, the service entrance conductors on the line side are energized and can kill you. Modern service panels provide an additional barrier over the line side lugs on the main breaker, but if yours is more than a few years old, those terminations may be exposed.

Regardless, you need to safely visualize all the terminal bars and understand how they are connected (or isolated). The term bus is generally reserved for the ungrounded busses at the back of the panel that the breakers connect to (although the neutral terminal bar may be referred to as a neutral bus, particularly in the newer "plug-on neutral" panels).

Click to expand...

This seems like a good time for me to yet again try and understand ground Vs neutral, if they are bonded somewhere along a common path. Care to have a go ?

----
In my home the service is a 300 Amp bundle that goes into the utility meter and then goes into a gutter box where it bifurcates into two large bundles (a parallel arrangement), each into a panel. The senior electrician said that one of the panels is the main panel and the other is a sub-panel even though I cannot see any difference between them. Each panel has a main breaker, and separate ground and neutral bars.

The first panel connected to the utility pole is the main panel. Assuming that the other one isn't also connected to the utility pole, that's the sub panel. If, as you suggest, they are connected in parallel to the same pole, then the difference must be in what each panel feeds.

Neutral is part of the normal path electrons take to supply current to an outlet or other load. Ground is an alternate path for current to take when there is a short circuit, so the breaker is tripped or fuse is blown. Without Grounding you can have a metal housing or conduit, energized by a short, that just sits there, Hot, waiting to electrocute the first person (and even subsequent persons) to touch it.

pr0lab said:

Thank you, Wayne. It is a service panel and it is a few years old. I don't have another disconnect above the panel (cables go right outside).

for the EVSE I am thinking of either something simple (w/o wifi) like this https://www.amazon.com/gp/product/B08B7WQHPZ/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 or more of a station like this https://www.amazon.com/dp/B08H2LYFH...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

The reason for selecting 6/3 UF was not to deal with conduit and not needing to have 2 separate cables as some of my cable runs outside (under the deck). Also it looks like the trend for the future it for more power hungry vehicles so I decided to install it once to support other cars in the future if needed (w/o having to redo)

Click to expand...

.

I really like the quality of the Nissan OEM EVSE. I believe it’s made by Panasonic. I have one I just listed on EBay that was never used, still in original bubble wrap http://ebay.us/KmMMnO?cmpnId=5338273189

I ended up with an extra EVSE after my 2019 SL+ was totaled last year and I replaced it with a 2020 SL+

LeftieBiker said:

The first panel connected to the utility pole is the main panel. Assuming that the other one isn't also connected to the utility pole, that's the sub panel. If, as you suggest, they are connected in parallel to the same pole, then the difference must be in what each panel feeds.

Neutral is part of the normal path electrons take to supply current to an outlet or other load. Ground is an alternate path for current to take when there is a short circuit, so the breaker is tripped or fuse is blown. Without Grounding you can have a metal housing or conduit, energized by a short, that just sits there, Hot, waiting to electrocute the first person (and even subsequent persons) to touch it.

Click to expand...

but larger wires have (like the 6/3 UF) need to be in a separate hole while grounds can be bunched together form other breakers if they fit in the hole, even if from 6/3 UF cable. This is from my understanding. in the main panel only.

Flyct said:

I really like the quality of the Nissan OEM EVSE. I believe it’s made by Panasonic.

Click to expand...

I'm not a fan because the Amps cannot be changed and it lacks adapter flexibility. It may be a quality build but it was engineered to be a cheap product for Nissan to buy in bulk. A large part of what makes a portable EVSE valuable is the ability to use it wherever one might end up.

Nissan cheap-skating, at its finest

pr0lab said:

while grounds can be bunched together form other breakers if they fit in the hole, even if from 6/3 UF cable.

Click to expand...

No, as mentioned twice, it's not enough just that they fit, the ground terminal bar has to be labeled as accepting more than one EGC of the size in question. 6/3 UF has a #10 EGC, so if the label says (2) #10s in a single ground terminal bar hole, that's fine, if you have another #10 it can share with. I think it's unlikely the label will say that a #10 and a #12 can share one ground terminal bar hole.

Cheers, Wayne

SageBrush said:

This seems like a good time for me to yet again try and understand ground Vs neutral, if they are bonded somewhere along a common path. Care to have a go ?

Click to expand...

Medium length answer:

The neutral comes from the utility and is part of carrying power to/from your house and its loads. The neutral is connected to the earth by the utility for their convenience.

The ground is a system that exists only within your property (no ground wire from the utility), and it connects together all the metal parts of the electrical system that shouldn't have any current on them, including the metal case of anything you plug in that has a 3 prong cord. The ground is connected to the earth; that eliminates, for example, the possibility of getting a big static build up on the metal case of equipment, that discharges when you touch it while connected to earth.

If the design stopped there, it would be a problem, as connections to earth are fairly high resistance. So if a "hot" (non-neutral) circuit conductor faulted to metal connected to the ground, current would flow through the earth, but not enough current to trip a breaker. Everything connected to ground would become a shock hazard.

So instead at the service where the ground system originates, there is one intentional connection between ground and neutral. That ensures that a hot-to-ground fault will carry enough current to trip the breaker. It's important that there not be any other ground-to-neutral connections in the system, as then the ground and neutral would be parallel, allowing the ground to carry some normal circuit current. That would possibly be a shock hazard, as wherever current is flowing, there is some voltage difference, which would cause some of the grounded metal to be at a potential different from earth.

Cheers, Wayne

SageBrush said:

In my home the service is a 300 Amp bundle that goes into the utility meter and then goes into a gutter box where it bifurcates into two large bundles (a parallel arrangement), each into a panel. The senior electrician said that one of the panels is the main panel and the other is a sub-panel even though I cannot see any difference between them. Each panel has a main breaker, and separate ground and neutral bars.

Click to expand...

That's an odd arrangement if it is really wired like that and I don't know what to say about it.

As for which is the service panel and which is a sub-panel, check if there is a (probably green) screw that ties the ground bar to the neutral in one box and not the other. Sub-panels can have a 'main' breaker in them but if used this way, the bonding screw that connects the ground bar to the neutral bar needs to be removed. It's not a big difference and could be easy to miss unless you specifically look for it.

wwhitney said:

pr0lab said:

while grounds can be bunched together form other breakers if they fit in the hole, even if from 6/3 UF cable.

Click to expand...

No, as mentioned twice, it's not enough just that they fit, the ground terminal bar has to be labeled as accepting more than one EGC of the size in question. 6/3 UF has a #10 EGC, so if the label says (2) #10s in a single ground terminal bar hole, that's fine, if you have another #10 it can share with. I think it's unlikely the label will say that a #10 and a #12 can share one ground terminal bar hole.

Cheers, Wayne

Click to expand...

Thank you, Wayne. I appreciate your response and for correcting me on this! I think the best path is to install another bus so I can add the neutral and ground onto two separate terminals/ holes. I have one spot left that I can run a jumper wire from to this new bus. Is there a particular wire that I need to use to run the jumper from one of the buses to this new bus?

Thanks again and appreciate your reply

pr0lab said:

I have one spot left that I can run a jumper wire from to this new bus.

Click to expand...

If you confirm the following are all true:

- All neutrals are terminated as a single wire in one hole.
- The panel label specifies that EGCs may be terminated as (2) #12 or (2) #14 in one hole.
- All EGCS are terminated as a single wire in one hole, except possibly some pairs of #12s or #14s.
- There are at least (2) #12 or (2) #14 EGCs currently terminated as single wires.

Then your simplest option is to take one of the single #12 or #14 EGCs, pair it with another currently single EGC of the same size, and put those both in the same hole. That will give you a second open spot, so you can terminate both your new neutral and EGC individually.

Other questions:

- What are the torque specifications for the terminal bars and the breaker terminals, and the 14-50 receptacle, and what torque screwdriver did you get?
- Did you get a 50 amp GFCI double pole breaker?
- Did you get a weatherproof box for your 14-50 receptacle, along with an "extra duty" weatherproof while in use cover for it? Or perhaps instead a self-contained 3R "RV power outlet box"?

Cheers, Wayne

wwhitney said:

what torque screwdriver did you get?

Click to expand...

I don't doubt the good advice, but I have yet to see an electrician use one.

SageBrush said:

I don't doubt the good advice, but I have yet to see an electrician use one.

Click to expand...

Then you've been watching the wrong electricians. This has always been a requirement, but the NEC has recently made it more explicit. New to the 2017 NEC:

110.14(D) Installation. Where a tightening torque is indicated as a numeric value on equipment or in installation instructions provided by the manufacturer, a calibrated torque tool shall be used to achieve the indicated torque value, unless the equipment manufacturer has provided installation instructions for an alternative method of achieving the required torque.

I admit that I only started doing this a couple years ago. I then went back and checked all the connections in my electrical panel, which I had made up with the "tighter is always better" philosophy. I found at least 2 breakers where I had overtightened the terminations so much that part of the lug was cracked, and I had to replace those breakers.

Cheers, Wayne

Can you suggest a good, reasonably priced torque screwdriver? I have to replace a breaker shortly. I may as well check the torque of the connections every time I work somewhere in the vast bowl of electric spaghetti that is our house.