Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 02-07-2011, 11:54 PM   #1
Member
 
Join Date: Nov 2009
Location: Langley, BC
Posts: 37
Share |
Default

Wire a subpanel or run separate lines?


We currently have a spa running off a 50A breaker in the service panel and a 50A GFCI in a "spa buddy" panel connected by 3AWG cable. From the spa panel to the spa is 3-conductor 3 AWG underground cable (with a 6AWG ground) which runs along the outside of the house above the cement sidewalk and attached to the lowest part of the cedar siding for about 40 feet. Eventually it does go underground for about 8' and comes up inside the spa.

We are getting ready to install a 2-ton heat pump which requires a 30A-40A breaker (depending on what we actually get) which will be installed close to the spa. Since we are also going to be vinyl siding the house, I would like to get rid of the large black cable that runs along the house and run it inside to a subpanel that contains a GFCI for the spa and a breaker for the heat pump.

From what I've read, running underground cable inside is not an issue, but:
  • Is the 3AWG copper underground cable sufficient to run to a subpanel to power both the spa and heat pump or should I just run a new line for the heat pump?
  • New cabling to the spa and heat pump: I feel that the PVC conduits look better than black cables - what size of PVC is required for the 40A spa and 30A heat pump? What conductor size should be used? These should also be individual conductors and not a cable correct?
  • How deep do the cables/PVC need to be in the ground?
Any suggestions are appreciated!

Mike

mlowrie is offline   Reply With Quote
Old 02-08-2011, 12:33 AM   #2
retired elect/hvac/plumb
 
plummen's Avatar
 
Join Date: Jan 2010
Location: south east of omaha/The island of misfit contractors
Posts: 2,895
Default

Wire a subpanel or run separate lines?


your looking at atleast 80a required to feed these 2 pieces of equipment,personally id feed it for a 100a outdoor panel/disconect fed with #2 cable and a seperate ground rod at the disconect point.
how big is service in house?

plummen is offline   Reply With Quote
Old 02-08-2011, 12:44 AM   #3
Member
 
Join Date: Nov 2009
Location: Langley, BC
Posts: 37
Default

Wire a subpanel or run separate lines?


Service right now is only 100A but we're waiting to see if we can get it upgraded to 200A (we have underground service - not sure if it is conduit or direct burial yet).

The underground service is rated for 125A but the panel is only 100A. I could just upgrade the wiring/panel to accommodate the 125A service and not worry about the 200A service upgrade which should be enough for the everything.
mlowrie is offline   Reply With Quote
Old 02-08-2011, 01:06 AM   #4
retired elect/hvac/plumb
 
plummen's Avatar
 
Join Date: Jan 2010
Location: south east of omaha/The island of misfit contractors
Posts: 2,895
Default

Wire a subpanel or run separate lines?


depending on what else you have in house thats not leaving much to run everything,does house have existing central air/heat pump?
plummen is offline   Reply With Quote
Old 02-08-2011, 11:42 AM   #5
Member
 
Join Date: Jun 2007
Posts: 3,503
Default

Wire a subpanel or run separate lines?


I have a feeling you are going to be upgrading this service before you do anything else. The heat pump alone may be what tips the scale. Why not take this opportunity to get 3 bids from licensed contractors to. (1) upgrade the service to 200 amp. (2) replace the cable running along the wall outside for the spa. (3) Run a new circuit for the heat pump?

I can assure you that you will need professional help in some way or another before this is finished. Why waste time and the aggravation, when you can get someone to do it for you. And do it for you the right compliant way.
J. V. is offline   Reply With Quote
Old 02-08-2011, 11:18 PM   #6
Electrical Supplier
 
Join Date: Jun 2010
Location: Dayton, OH
Posts: 205
Default

Wire a subpanel or run separate lines?


@ plummen, no ground rod is needed for this installation.

@ OP what is the wire TYPE that is used, "Underground" doesnt tell us enough. I need to know the temperature ratings and the insulation ratings.

UF-B is 60 degree wire while USE, RHH, RHW and RHW-2 are 75 and 90 degree ratings.

#3 copper (4 total wires, 3 conductors and a ground) CAN be used to the following ampacities

If Type UF-B: 85 amps,

Type USE, RHH and RHW: 100 amps

Type RHH-2 and RHW-2: 110 amps

The only issue I see with an inspection is this :
Quote:
which runs along the outside of the house above the cement sidewalk and attached to the lowest part of the cedar siding for about 40 feet. Eventually it does go underground for about 8' and comes up inside the spa.
This IMO is subject to physical damage and should be inside the appropriate conduit. Conduit the wire and install an outdoor/NEMA 3R 8 circuit panel.

You will require the following minimal breakers:

2 poles for main disconnect,
2 poles for SPA
2 poles for A/C
and 1 pole for your Outside GFCI protected outlet to service the A/C unit (Dont forget that of course!)
__________________
"Do it right the first time and avoid duplication of effort"

Your AHJ/Inspectors ALWAYS have the final say on ANY electrical code issue.
If in doubt, contact a licensed, experienced, reputable electrician to perform the work.
LyonsElecSupply is offline   Reply With Quote
Old 02-09-2011, 01:57 AM   #7
Member
 
Join Date: Nov 2009
Location: Langley, BC
Posts: 37
Default

Wire a subpanel or run separate lines?


Looks like the heat pump we are slated to get is Lennox XP19 which requires a 25A breaker (Listed as "Maximum overcurrent protection). A few amps less than I originally anticipated.

J.V.
Our hydro company will perform all the work up to the meter if the service is in conduit. I will upgrade the panel myself and have it inspected. The hydro company will not replace the meter until inspected.

If the cable is direct burial, I will simply shut the spa down until I can get new service run as I'll have to dig up a good chunk of my front yard to get to the hydro box. Need the experts for that one.. a little too much $$$ right now if I need to go that route.

Plummen:
No heat pump/central air installed - just standard forced-air gas furnace right now

LyonsElecSupply:
I'm trying to figure out what the cable is as I cannot find any markings on it. It is simply armored cable with a waterproof sheath around it. I'll see if I can "dig" anything up on it.

Here in Canada, I don't believe we need a spa shutoff located outside in sight of the spa. I'll double check the code to verify.

I'll also do a load calc for the house to see what the capacity is. Is 3AWG sufficient for 125A service wiring for ~2' run? I just don't feel like searching the code book this late in the day....

Once I have some better numbers I list out the "plan".

BTW, in my area homeowners can do the work themselves and have the safety authority inspect the work. I plan on getting a permit and having it inspected before I throw the switch on!

Mike
mlowrie is offline   Reply With Quote
Old 02-09-2011, 07:19 AM   #8
retired elect/hvac/plumb
 
plummen's Avatar
 
Join Date: Jan 2010
Location: south east of omaha/The island of misfit contractors
Posts: 2,895
Default

Wire a subpanel or run separate lines?


Quote:
Originally Posted by LyonsElecSupply View Post
@ plummen, no ground rod is needed for this installation.

@ OP what is the wire TYPE that is used, "Underground" doesnt tell us enough. I need to know the temperature ratings and the insulation ratings.

UF-B is 60 degree wire while USE, RHH, RHW and RHW-2 are 75 and 90 degree ratings.

#3 copper (4 total wires, 3 conductors and a ground) CAN be used to the following ampacities

If Type UF-B: 85 amps,

Type USE, RHH and RHW: 100 amps

Type RHH-2 and RHW-2: 110 amps

The only issue I see with an inspection is this :


This IMO is subject to physical damage and should be inside the appropriate conduit. Conduit the wire and install an outdoor/NEMA 3R 8 circuit panel.

You will require the following minimal breakers:

2 poles for main disconnect,
2 poles for SPA
2 poles for A/C
and 1 pole for your Outside GFCI protected outlet to service the A/C unit (Dont forget that of course!)
im sure you could get away without the extra ground rod but it wouldnt hurt to have extra grounding with the hot tub i figure
plummen is offline   Reply With Quote
Old 02-09-2011, 10:04 AM   #9
Licensed electrician
 
Join Date: Sep 2007
Location: Maryland
Posts: 7,501
Default

Wire a subpanel or run separate lines?


There is no need for a ground rod for the hot tub or a subpanel in an attached building.
__________________
Answers based on the National Electrical Code. Local amendments may apply. Check with your local building officials.
Jim Port is online now   Reply With Quote
Old 02-09-2011, 07:41 PM   #10
Electrical Supplier
 
Join Date: Jun 2010
Location: Dayton, OH
Posts: 205
Default

Wire a subpanel or run separate lines?


Ground rods DO NOT "ground" or provide a true current path. Ground rods just equalize the voltage potential among different connections.

Now, what you will need (at least in the USA) is a bonding ring around the spa........
__________________
"Do it right the first time and avoid duplication of effort"

Your AHJ/Inspectors ALWAYS have the final say on ANY electrical code issue.
If in doubt, contact a licensed, experienced, reputable electrician to perform the work.
LyonsElecSupply is offline   Reply With Quote
Old 02-09-2011, 07:51 PM   #11
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 978
Default

Wire a subpanel or run separate lines?


Quote:
Originally Posted by LyonsElecSupply
Ground rods DO NOT "ground" or provide a true current path. Ground rods just equalize the voltage potential among different connections.

Now, what you will need (at least in the USA) is a bonding ring around the spa........
Rods DO "ground" and they DO provide a true path for current. Just not a path of low resistance. Rods don't protect people from faults.
jlmran is offline   Reply With Quote
Old 02-09-2011, 07:53 PM   #12
Member
 
Join Date: Nov 2009
Location: Langley, BC
Posts: 37
Default

Wire a subpanel or run separate lines?


I found out what cable it is. Teck90 but it's only 6AWG. It's Belden C5591 cable.

I'm thinking I'll need to get something larger to run the spa and heat pump.
mlowrie is offline   Reply With Quote
Old 02-09-2011, 08:43 PM   #13
Electrical Supplier
 
Join Date: Jun 2010
Location: Dayton, OH
Posts: 205
Default

Wire a subpanel or run separate lines?


Quote:
Originally Posted by jlmran View Post
Rods DO "ground" and they DO provide a true path for current. Just not a path of low resistance. Rods don't protect people from faults.
Read 250.2...........it minimizes voltage to ground and to stabilize voltage to earth under normal operations.

for a ground rod to be even remotely effective as a true grounding conductor (IE providing a true path for current return) it would have to be 5/8" dia and about 50 feet long. Ive seen an electrical engineer write it out..in fact, they are now putting rebar in foundations of houses, this provides the BEST way to ground an electrical system.

What it IS is a fail safe device but mostly just a stabilizer. A ground rod at a subpanel is NOT the ground path, the 4th wire is the ground path. All the ground rod does is stabilize the voltage potential between the two locations.
__________________
"Do it right the first time and avoid duplication of effort"

Your AHJ/Inspectors ALWAYS have the final say on ANY electrical code issue.
If in doubt, contact a licensed, experienced, reputable electrician to perform the work.
LyonsElecSupply is offline   Reply With Quote
Old 02-09-2011, 09:01 PM   #14
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 978
Default

Wire a subpanel or run separate lines?


Quote:
Originally Posted by LyonsElecSupply

Read 250.2...........it minimizes voltage to ground and to stabilize voltage to earth under normal operations.

for a ground rod to be even remotely effective as a true grounding conductor (IE providing a true path for current return) it would have to be 5/8" dia and about 50 feet long. Ive seen an electrical engineer write it out..in fact, they are now putting rebar in foundations of houses, this provides the BEST way to ground an electrical system.

What it IS is a fail safe device but mostly just a stabilizer. A ground rod at a subpanel is NOT the ground path, the 4th wire is the ground path. All the ground rod does is stabilize the voltage potential between the two locations.
How does this change the truth of what I wrote?
jlmran is offline   Reply With Quote
Old 02-15-2011, 11:28 PM   #15
Member
 
Join Date: Nov 2009
Location: Langley, BC
Posts: 37
Default

Wire a subpanel or run separate lines?


I will check the spa to see what it currently has in terms of a ground rod. I don't think it has one and I don't see any requirement for ground rods regarding spas in the Canadian Electrical Code.

I'm just about ready to put everything together, but I have one question. The branch circuit to the sub-panel will require an 80-100A to power the spa and heat pump. The spa requires a 50A GFCI. Since I will be supplying the spa with 6AWG, does that mean I have to put in a 50A breaker in the sub-panel before the GFCI in order to protect the wiring?

Mike

mlowrie is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
240v conduit with different gauge wires... Biospot Electrical 7 12-14-2010 07:07 PM
HVAC three wire motor to six wire motor Leo Caproni HVAC 5 10-18-2010 01:23 PM
running wire for subpanel rek Electrical 3 09-22-2010 10:09 PM
Wire options for a 70 amp subpanel mtaviator Electrical 5 01-11-2008 07:46 PM
Reverse Polarity at the Subpanel adm060306 Electrical 14 07-09-2007 12:58 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.