Increase electrical service to shop


  #1  
Old 07-11-15, 09:33 PM
L
Member
Thread Starter
Join Date: Jul 2015
Location: Canada
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
Increase electrical service to shop

I Live in Canada and my problem is this: 40 years ago a shop was built on my property, 10 years later another shop was built and 10 years after that our house was moved on.
The way these were wired is that the first shop has the 200 amp entrance and main panel, which has a 100 amp breaker running power to the house. On the way to the house a junction box was placed on the outside of the second shop with 3 - 10 Gauge wires feeding the 30 amp sub-panel inside.
Is there anyway I can get 100 amps at the second shop?
I know I can easily increase the wire size, from the junction box to the sub-panel, to 8 gauge and get a 40 amp sub-panel but i would like more power to run welders, woodworking tools, maybe a car lift, etc...

Here is the photo of the junction box on the outside of second shop, the 3 wires at the top right are the 10 gauge wires feeding the 30 amp sub-panel inside the shop.
Name:  20150711_192457_resized_1.jpg
Views: 3964
Size:  34.3 KB

So, in the end, I'd have 100a service at shop#1, (40-100a?) at shop#2 and 100a at house.
thanks
 

Last edited by ray2047; 07-12-15 at 12:15 AM.
  #2  
Old 07-11-15, 10:04 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 29,711
Upvotes: 0
Received 15 Upvotes on 13 Posts
Never heard of a spliter but the junction box in your picture probably needs to be replaced with a breaker box. I doubt even under tap rules you could connect the #10 without a breaker. I'd say replace the junction box in the picture with a 100a combo main breaker/main lug panel. Power from the first shop to the main breaker. Power for the house from the main lugs. Install a breaker for the second shop. Perhaps a 60 amp breaker and use #6 to feed the second shop.
 
  #3  
Old 07-11-15, 10:24 PM
L
Member
Thread Starter
Join Date: Jul 2015
Location: Canada
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
Sorry, ray2047, I did not word my original post correctly, I have edited to be more clear. Also, If I have to trench new wire or anything like that to achieve my goals please let me know. Also, will I need a grounding rod here to use 220-240v? thanks
 

Last edited by lab_rat; 07-11-15 at 11:19 PM.
  #4  
Old 07-12-15, 12:12 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 29,711
Upvotes: 0
Received 15 Upvotes on 13 Posts
Every subpanel needs at least one ground rod (GEC) and sometimes two depending on local code. Every subpanel (120/240) must have four wires, two hot, one neutral one ground wire (EGC). The new box you are putting in is a subpanel and will need a ground wire (EGC) from the main panel and a ground rod (GEC). The feed to the house and the feed to the second shop will also need ground wires (EGC).

Note ground rods (GEC) do not serve the same purpose as the ground wire (EGC). You must have both.

GEC, Ground Electrode Conductor, provides protection from atmospheric charge build up.
EGC, Equipment grounding conductor, provides a low resistance path for shorts to the metal of an appliance or fixture.
 
  #5  
Old 07-12-15, 04:30 AM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 16,321
Received 38 Upvotes on 30 Posts
I can't cite CEC rules but in the US at the time this "splitter" panel was installed the tap wires would have been code compliant as long as they were no more than ten feet long from the tap to the sub-panel AND there was either a main circuit breaker/fuse OR no more than six branch circuits in the sub-panel.

The biggest problem that I see is that both the second shop and the house are sharing the 100 amperes available on the feeder from the first shop. I would suggest that a new run (to replace the existing) from the first shop to the second shop with a four-conductor run rated for at least 150 amperes and maybe 200 amperes to a sub-panel as Ray described at the second shop. (The proper name for the sub-panel would be a main breaker type with feed-through lugs.) You could still use a tap box like you have as long as it was rated for the increased amperage and the tap connections to second shop panel met the current rules for taps and the wiring to the house was of sufficient size to handle the full amperage available from the branch circuit breaker in the first shop panel feeding the second shop and house.

On the other hand, a complete rewiring of the supply to all three buildings might actually be a better idea.
 
  #6  
Old 07-12-15, 05:49 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 14,269
Received 860 Upvotes on 723 Posts
The wire in the junction box looks to be much larger then needed for 100 amps. What size is that wire? What is it fused at in the main panel? Perhaps a picture of the main panel would help as well.

The tap rules that Furd mentioned will come into play here. How far is the panel in shop #2 from the junction box?
 
  #7  
Old 07-13-15, 12:44 PM
L
Member
Thread Starter
Join Date: Jul 2015
Location: Canada
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
The wire size coming from the 100 amp fuse #9-12 from the main panel (see below) is: 1/0 awg black wire and 2 awg white wire, so it looks like Aluminum USEI-90 Underground Secondary Cable, 4 Conductor / Reduced Neutral with a max Ampacity rating of 120amps. The junction box is on the second shop itself and the sub-panel is directly behind it, so about 1 to 2 feet away.
Name:  mainpanel.jpg
Views: 704
Size:  21.5 KB

thanks
 

Last edited by lab_rat; 07-13-15 at 02:14 PM.
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: