Landscape Electrical

[agolestani]

Hi all,

I've done many projects in the past where we run pvc conduit into the ground from the main, and uf after the elbow underground in a 12" trench, (In LA so no frostline). The uf goes to a shed or maybe an outdoor kitchen and is connected there to a GFCI/swith combo box to account for the disconnect and GFCI requirements. From there, everything is run within the shed or kitchen frame with NM-B or whatever may be the case.

My question is regarding more rigorous landscaping electrical, and more specifically an MWBC. Pergola lighting, patio step lighting, and some electrical outlets is the task. After the UF comes out of the ground to the first GFCI Outlet switch, it reburied to reach the next junction near a pergola post or patio step light.

Is it okay to rebury wire after the initial gfci/switch box? Or is there another proper method?

Thanks in advanced.

 

[kingpb]

Personally, I'd do all the lighting in LV system, and only wory about recep as 120V. As far as the cable, I think as long as it is sleeved in can go up and back down.

 

[jumper]

Your 12" trench for the UF from the panel is a violation of 300.5. 18" minimum unless you meet the requirements of Column 4. Your direct burial cable after the GFCI might meet the 12" minimum.

I am assuming this is a residential install.

 

[agolestani]

Your 12" trench for the UF from the panel is a violation of 300.5. 18" minimum unless you meet the requirements of Column 4. Your direct burial cable after the GFCI might meet the 12" minimum.

I am assuming this is a residential install.

Interesting, never been called out on it. The line is actually running from a outdoor sub panel attached to the home where the main is also attached. Circuits are 20 amps or less as well as 120volts. Not supported by a GFCI as UFC is going underground, only as it is coming out. Does that not meet the requirements of column 4? I may have interpreted it differently.

 

[GerryB]

Interesting, never been called out on it. The line is actually running from a outdoor sub panel attached to the home where the main is also attached. Circuits are 20 amps or less as well as 120volts. Not supported by a GFCI as UFC is going underground, only as it is coming out. Does that not meet the requirements of column 4? I may have interpreted it differently.

Thr gfi protection needs to be at the beginning of the circuit before it goes underground is my understanding. The code handbook has an explanation to that effect.

 

[agolestani]

Thr gfi protection needs to be at the beginning of the circuit before it goes underground is my understanding. The code handbook has an explanation to that effect.

I see, did some more digging around in the book. I was initially under the impression that the GFI would be placed after the UF resurfaced (In the direction of panel -> Ground-> Resurface->GFCI). Is there then also not a need for a disconnect switch after it comes out of the ground (This was another thing I thought was common but can't pinpoint it in the book).

I think for my purposes, ill just use a GFI breaker instead of regular breaker at the sub panel (50 amp subpanel, fed by regular 50amp breaker in main), keep the trench at 12 inches all throughout.
Never used a GFI breaker like this, anyone see any potential issues? Should I also scrap and disconnect switch(I usually use a typical light switch in wet location rated box).

Thanks.

 

[jumper]

Switch not needed. A dead front GFCI installed at panel is way cheaper than breaker.

 

[agolestani]

Switch not needed. A dead front GFCI installed at panel is way cheaper than breaker.

Had the same Idea, then realized I would need 4 dead fronts. 12/3 going to electrical outlets/lighting and another 12/3 going to kitchen (Keeping disposal/fridge/lighting/receptacles separate).

Hate that I'm a neat freak, 4 gang box will look cluttered IMO, its an expensive "good" habit.

 

[jxofaltrds]

I see, did some more digging around in the book. I was initially under the impression that the GFI would be placed after the UF resurfaced (In the direction of panel -> Ground-> Resurface->GFCI). Is there then also not a need for a disconnect switch after it comes out of the ground (This was another thing I thought was common but can't pinpoint it in the book).

I think for my purposes, ill just use a GFI breaker instead of regular breaker at the sub panel (50 amp subpanel, fed by regular 50amp breaker in main), keep the trench at 12 inches all throughout.
Never used a GFI breaker like this, anyone see any potential issues? Should I also scrap and disconnect switch(I usually use a typical light switch in wet location rated box).

Thanks.

GFCI the 'sub' panel. We saying the same thing?

 

[FREEBALL]

Are you aware of the common trip rule of curcuits when you are sharing neutrals like that ???? May be more also you said landdscape now kitchen anyway 4 dead fronts will not suffice more info is needed i think ???

 

[agolestani]

GFCI the 'sub' panel. We saying the same thing?

Don't think so. GFCI the subpanel to me means to swap out the existing 50 amp breaker in the main to a 50amp gfci breaker. What I meant was multiple 20 amp gfci breakers inside the subpanel, right before the circuits hit the ground. Ofcourse for a MWBC, a handle-tie would be placed for the pair of gfci breakers.

 

[agolestani]

Don't think so. GFCI the subpanel to me means to swap out the existing 50 amp breaker in the main to a 50amp gfci breaker. What I meant was multiple 20 amp gfci breakers inside the subpanel, right before the circuits hit the ground. Ofcourse for a MWBC, a handle-tie would be placed for the pair of gfci breakers.

Freeball,

I think this may have answered your question too. Yes, I was inquiring about the landscape because of the in and out from underground. The kitchen will be on its own seperate mwbc circuit, two single pole breakers, handle ties, (all the goodies).

 

[FREEBALL]

Thankyou for clarifying that thats all I have

 

[agolestani]

Thankyou for clarifying that thats all I have

Thanks for chiming in anyways, always open to be corrected or even better, learn a better way of going about a job.

 

[GerryB]

Don't think so. GFCI the subpanel to me means to swap out the existing 50 amp breaker in the main to a 50amp gfci breaker. What I meant was multiple 20 amp gfci breakers inside the subpanel, right before the circuits hit the ground. Ofcourse for a MWBC, a handle-tie would be placed for the pair of gfci breakers.

I think you need a 2-pole 20a gfi breaker since you only have one neutral, probably cost about the same as two single poles. (Or you could kinda forget about it till the next time) In your defense I've run into a few inspectors that were unsure on this and usually just said "18 inches".

 

[agolestani]

I think you need a 2-pole 20a gfi breaker since you only have one neutral, probably cost about the same as two single poles. (Or you could kinda forget about it till the next time) In your defense I've run into a few inspectors that were unsure on this and usually just said "18 inches".

You would think so right? Although I don't get my stuff from here.... Home Depot sells single pole gfi 20 amp for $37 and double pole for $105. That's Bananas!!

Supply and demand! It can turn on you in an instant.:lol:

 

[readydave8]

You would think so right? Although I don't get my stuff from here.... Home Depot sells single pole gfi 20 amp for $37 and double pole for $105. That's Bananas!!

Supply and demand! It can turn on you in an instant.:lol:

I think the point is that 2 GFCI breakers w/ handle tie may not work on multiwire circuit, if the 2 hots are sharing a neutral, how could it work?

 

[agolestani]

I think the point is that 2 GFCI breakers w/ handle tie may not work on multiwire circuit, if the 2 hots are sharing a neutral, how could it work?

You are correct. The neutral wire comes out of each breaker. Tieing one to two single poles will cause instant trips. Need to find cheeper dp gfi breakers. :slaphead: Thanks for input!