How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask Kevin Your Own Question

Kevin
Kevin, Licensed Electrician
Category: Electrical
Satisfied Customers: 1134
Experience:  27 years as a Licensed Electrical Contractor in Illinois, 5 year college Electrical Instructor, Former Electrical Inspector, Diploma in Digital Electronics, Former Illinois Licensed Home Inspector
71008832
Type Your Electrical Question Here...
Kevin is online now
A new question is answered every 9 seconds

The underground wire that comes from my house panel to my workshop

Resolved Question:

The underground wire that comes from my house panel to my workshop panel is yellow. It separates from the red and black wire and connects to the ground that goes under the building to the buried ground. On my new panel purchased for the shop I have two main lugs that I assume is fro the red and black wires. Does it matter which goes to which? There is a row of connectors on the right side of the box. At the top is a green screw under that is a row of lugs. On the row of connectors do I put the white wires from my circuits and black goes on the breaker itself. I would guess the buried ground goes to the green screw and that leaves me unsure where the grounds for the circuits go. perhaps on the breaker itself? I have done some wiring before but never installed a new panel. I don't want to mess it up.
Submitted: 1 year ago.
Category: Electrical
Expert:  Kevin replied 1 year ago.

Hello.....my name is XXXXX XXXXX I will be happy to assist you with your electrical question. My goal is to exceed your expectations on Just Answer!


Hello Jim....... before I can provide you with an answer to your questions, I need some additional information as shown below.........Thanks.........Kevin!

 

1) What is the wire size of the existing underground yellow wire originating from the house to the workshop panel?

 

1A) Do you plan on re-using that wire?

 

1B) Does the yellow wire have a labeling on the exterior insulation indicating NM or Non-Metallic or UF or Underground Feeder?

 

1C) Is this Romex cable with 4 individual conductors (black, red, white and bare copper ground wire) all installed within a yellow exterior insulation to form 1 cable?

 

2) Does the existing underground feeder wire contain (4) four conductors, ie, 2 hots, 1 neutral and 1 ground?

 

3) Is the yellow wire a direct burial or installed in conduit? If in conduit, what is the diameter and type of conduit? Gray PVC Electrical conduit, EMT, Rigid Metal?

 

4) How many amps will the feeder circuit for the workshop sub-panel be? Will you be using a 100 amp double pole circuit breaker in your main electrical panel to feed the Siemens sub-panel?

 

5) Can you provide me with the approximate distance from your main electrical panel to the workshop? I need to calculate the voltage drop based upon the feeder wire size and distance.

 

6) Does the shop have an existing 8 foot ground rod?

Customer: replied 1 year ago.

So sorry about the confusion. I was asking things without enough sleep.


1a) The wires coming from the house breaker are 8gague.
1b) I see nothing like that on the wire.
1c) No this is a braided wire with the black red & yellow covering over the copper wire.
2) No it is red, black and the yellow as above.
3) I see no evidence of conduit on the house or shop side.
4) The electrician who set up my 200amp service in the house has the shop hooked to a double 40 amp breaker.


5) best estimate would be about 40'


6) yes it does

Expert:  Kevin replied 1 year ago.

Hello Jim...........thanks for the replies.

 

1) In your initial question, the optional information is mentioned as a Siemens 100 amp main breaker panel. I am assuming this is the sub-panel that you would like connected for your shop? If looking to retain the 40 amp feeder breaker inside the 200 amp main panel, let me know as my answers below will change. My answers below are based on using the 100 amp main breaker sub-panel. If otherwise, let me know...........Thanks........Kevin!

 

2) 8 AWG Stranded copper wire is only rated as 40 amps and this wire size is too small if you are desiring to connect it to the 100 sub-panel. A 100 amp main breaker sub-panel will require 2 AWG Stranded Copper or 1/0 AWG Stranded Aluminum conductors as the feeder cables, 2 hots and 1 neutral from your 200 amp main electrical panel in the house. The equipment grounding conductor will need to be size 8 AWG Stranded copper. I would recommend to use 2 AWG Stranded copper since the distance is only 40 feet away. Therefore, the 4 conductors are as follows:

 

Quantity of (2) two 2 AWG Stranded copper conductors for the hots

Quantity of (1) one 2 AWG Stranded copper conductor for the neutral

Quantity of (1) one 8 AWG Stranded copper conductor for the equipment ground

 

The (4) four conductors need to be rated as THWN insulation for wet conditions if using a underground conduit system or Underground Feeder cable (UF).

 

I calculated the voltage drop using 240 volts, 40 foot distance, 100 amps as the load and 2 AWG Copper wires. The voltage drop is only .6 percent which is way less than the recommended 3% maximum voltage drop. Therefore, 2 AWG copper will work fine.

 

3) All sub-panels require 4 conductors, ie, 2 hots, 1 neutral and 1 equipment ground. This is an electrical code requirement.

 

4) You will need either the 2 AWG copper or the 1/0 Aluminum to be Underground Feeder cable rated if installing as a direct burial or you would need to install a minimum conduit diameter of 1 1/4" if not using UF cable. If considering conduit, you can either install Schedule 40 Gray electrical PVC conduit or Rigid Metal conduit. I would recommend the Schedule 40 Gray electrical PVC since this is a more cost effective solution. I would also recommend to bump up the conduit diameter to 1 1/2" in order to make the wire pull easier.

 

If using Rigid metal conduit, then the equipment grounding conductor is not required since the rigid metal conduit would be acting as the equipment ground. UF cable will need to be trenched a minimum of 24 inches. PVC conduit will need to be trenched a minimum of 18 inches. I would also recommend to use the PVC conduit, since you only want to trench this once. The underground conduit system is a better solution in the event of any faulty conductors or troubleshooting purposes down the road.

 

If removing the concentric knockouts at either panel, you will also require a bonding bushing. Use 8 AWG Stranded copper from the bonding bushing and terminate to the respective equipment ground bar at each panel. If not removing a concentric knockout, then the bonding bushing is not required.

5) The 200 amp main breaker panel will require a double pole 100 amp breaker. The 2 AWG conductors will land on the 100 amp breaker inside your main electrical panel. The 2 AWG neutral conductor will land on the main neutral bus within your main panel. The main panel will require an equipment ground bar which will land the 8 AWG equipment grounding conductor. Use some electricians tape and tape the 2 hots as red and black or red and blue. Tape the neutral as white and the equipment ground as green. The color code of the tape will identify the 4 conductors. Tape the respective conductors at each end.

 

6) At the sub-panel, the 2 hots get terminated on the 100 amp main breaker. Does not matter which screw of the main breaker the hots will land on. The neutral wire lands on the neutral bus bar in the sub-panel. If the sub-panel is not equipped with an equipment ground bar, you will need one. The 8 AWG equipment ground lands on the equipment ground bar inside the sub-panel.

 

Do not intermix the equipment ground and the white neutral in the sub on the same bus bar. They need to land on two separate bus bars for safety reasons. In all sub-panels, the neutral conductor must remain isolated from the metal cabinet enclosure. Therefore, do not install the green grounding screw or the copper main bonding jumper strap inside the sub-panel. The neutral wire must float inside the sub.


7) Connect the 8 AWG equipment ground wire from the sub-panel equipment ground bar to the existing 8 foot ground rod.

 

8) If using Non-metallic cable (Romex) within the shop area, the bare copper grounding conductors only land on the equipment ground bar and not on the neutral bus bar. The equipment grounds and neutrals must remain separated within a sub-panel. Bare coppers to the equipment ground bar and the white neutrals to the neutral bus bar. Do not intermix these two.

 

9) For any receptacles within the shop either consider installing 20 amp GFCI branch circuit breakers or use 20 amp GFCI receptacles on the LINE side and regular 15 or 20 amp duplex receptacles on the LOAD side of the GFCI receptacle. The use of a 20 amp GFCI receptacle is a more cost effective solution.

 

10) Within the shop, I recommend that the branch circuits for the receptacles and lighting be on separate circuit breakers.

 



Hope this helps.........If you have any additional questions, let me know and I'll be glad to answer them for you.

 

Otherwise, don't forget to rate me before you log Off.

The next time you have an electrical question, you can also request for me at:http://www.justanswer.com/home-improvement/expert-your-electrician
..........Thanks..............Kevin!



Kevin, Licensed Electrician
Category: Electrical
Satisfied Customers: 1134
Experience: 27 years as a Licensed Electrical Contractor in Illinois, 5 year college Electrical Instructor, Former Electrical Inspector, Diploma in Digital Electronics, Former Illinois Licensed Home Inspector
Kevin and 4 other Electrical Specialists are ready to help you
Customer: replied 1 year ago.


So am I getting that if the underground wire is 8g I need to have a heavier wire buried in the ground? SInce I will not be using heavy equipment such as a welder or big compressor would current wire be acceptable if I remove the 100 amp main breaker in the sub panel and replace with a 40 amp breaker?

Expert:  Kevin replied 1 year ago.

1) Yes, that is correct Jim, if you want to install the 100 amp breaker in the sub-panel, then the wires need to be sized as per my previous reply.

 

2) If you want to use a 40 amp breaker for the sub-panel, the 8 AWG copper wires are OK, but keep in mind that the sub-panel requires 4 conductors, ie, (2 hots, 1 neutral and 1 equipment ground). If using a 40 amp breaker, you will require a quantity of (3) three 8 AWG's (2 hots and 1 neutral) and (1) one 10 AWG copper for the equipment ground. If using the 40 amp breaker in the sub, the minimum conduit size is 3/4". However, I would recommend to bump it up one size and use 1" diameter conduit to make the wire pull easier. The additional cost to increase the conduit is minimal.

 

3) If using a 40 amp breaker for the new sub, I would recommend that you only install a maximum of (4) four circuits. Since the new Siemens sub-panel has spaces for 20 circuits, if you load more than 4 circuits using a 40 amp breaker and the 8 AWG feeder wires, you will end up overloading the 40 amp breaker since the 8 AWG feeders will not be able to carry a load greater than 4 circuits. The 100 amp breaker is OK to max out the sub-panel using all 20 circuits. If using a 40 amp breaker in the sub, do not insert more than the 4 circuits. A 40 amp sub-panel is not meant for 20 circuits.

 

Jim........Thank you for the positive service rating as well as the bonus............much appreciated!

 

If you have any other questions, just let me know.

 

Take care and have a great day............Thanks...............Kevin!

Kevin, Licensed Electrician
Category: Electrical
Satisfied Customers: 1134
Experience: 27 years as a Licensed Electrical Contractor in Illinois, 5 year college Electrical Instructor, Former Electrical Inspector, Diploma in Digital Electronics, Former Illinois Licensed Home Inspector
Kevin and 4 other Electrical Specialists are ready to help you

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
< Last | Next >
  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland
 
 
 

Meet The Experts:

 
 
 
  • Mike

    Master Electrician

    Satisfied Customers:

    1425
    Licensed Master Electrician - OnQ Certified Data Voice Audio Video Installer
< Last | Next >
  • http://ww2.justanswer.com/uploads/mikepettinato/2009-9-4_41145_DSC005132.jpg Mike's Avatar

    Mike

    Master Electrician

    Satisfied Customers:

    1425
    Licensed Master Electrician - OnQ Certified Data Voice Audio Video Installer
  • http://ww2.justanswer.com/uploads/WI/WireitUp/2012-6-17_18212_Photo00006.64x64.jpg Jason's Avatar

    Jason

    Service Technician

    Satisfied Customers:

    3278
    Over 15 years of experience in all types of installations, troubleshooting, and repairs.
  • http://ww2.justanswer.com/uploads/MI/MikeG2010/2012-6-7_192640_IMG01612.64x64.jpg Mike G.'s Avatar

    Mike G.

    Master Electrician

    Satisfied Customers:

    5318
    Proven Professional 45 years Experience
  • http://ww2.justanswer.com/uploads/AS/AssuredElectrical/2011-9-13_221243_me.64x64.gif AssuredElectrical's Avatar

    AssuredElectrical

    Master Electrician

    Satisfied Customers:

    2149
    Contractor-40 Years in the ElectricalTrade
  • http://ww2.justanswer.com/uploads/electrifier/2008-12-16_200429_headbob1.jpg electrifier's Avatar

    electrifier

    Master Electrician

    Satisfied Customers:

    1454
    Electrical contractor and electrical inspector for over 24 years with phone and networking expertise
  • http://ww2.justanswer.com/uploads/rich03dungo/2010-3-17_101556_tshirt2.jpg Rich's Avatar

    Rich

    Master Electrician

    Satisfied Customers:

    1115
    Over 35 years residential, commercial, industrial wiring, install, troubleshoot, service, maintain
  • http://ww2.justanswer.com/uploads/UR/urelectrician/2012-9-28_223652_JustAnswerPic.64x64.jpg Kevin's Avatar

    Kevin

    Licensed Electrician

    Satisfied Customers:

    993
    27 years as a Licensed Electrical Contractor in Illinois, 5 year college Electrical Instructor, Former Electrical Inspector, Diploma in Digital Electronics, Former Illinois Licensed Home Inspector