Need Help for 240V from House to Garage

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  #1  
Old 05-31-17, 09:54 AM
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Need Help for 240V from House to Garage

Hi, Great Forum!!!

I am looking to install a pool heater for my above ground pool just wanted some clarifications before i begin this project.

I have tried to find answer for this simple questions, but just couldn't find any.

I reside in Lynbrook NY, And i like to install a 240V 30 amp GFCI load center for a pool heater. The issue is the load center would be located near the back of the garage away from my home. The garage currently does not have 240V it currently only has 2 - 115V to dedicated circuits.

The issue is everything around my garage is concrete and blacktop and impossible to get a new conduit to the garage. I currently have a 3/4 inch conduit with one 115V i do not think i can get another cable in there and first and most there is definitely no trace left behind.

There is an existing 240V AC outlet that is not being used in the house that i can pull out the wall facing the yard and just place blank wall plate in the house.

My questions

Option 1 does the conduit have to buried underground or can it be placed under the existing step heading from the house to the garage.

Option 2, can i run a 240V cable in the current conduit that has a 115V circuit already in the conduit?

Please view the pic

Any ideas would be much much appreciated

Thank you
Eddie

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  #2  
Old 05-31-17, 10:10 AM
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How much power does the pool heater need?

If it needs almost the entire 30 amps at 240 volts then you need at least three 8 gauge wires (and a 10 gauge ground) going out to the garage which gives you both 120 and 240 volts. This will give you 40 amps @ 240 volts total which leaves some for the receptacles.

The existing 120 volt circuit needs to be decommissioned as only one feed is allowed between any two buildings. So you might as well withdraw that while pulling the new wires through the conduit.

You will need to double check whether the conduit will accommodate the #8 wires or better yet will accommodate three #6 (and one #10) for future additional power needs in the garage area.

Separate conductors (THWN style) would be better than a cable as you can get more current carrying capability in a given conduit and also would be easier to pull.
 

Last edited by AllanJ; 05-31-17 at 10:32 AM.
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Old 05-31-17, 10:37 AM
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Hi Allan

Here is what i have found from the heater specs and speaking with the technical service department, it will need the following.
240 vac, 30 amp power source as well as a 30 amp GFCI load center,
The heater is a 5500 Watt pass thru element at 240V, from my calculations it seems it will use 23 Amps while running

Well here is my other issue.
1 - 115V circuit power my garage interior lights and 2 outlets
1 - 115V circuit powers my pool pump,Salt Water Chlorine Generator, that same circuit power a LED TV when the pump and the SWCG are not on.
Eliminating any of the 2 circuit will not work for me.

Please advise
 
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Old 05-31-17, 11:30 AM
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Two black #6 THWN (or one black, one red) plus one white #6 THWN plus one #10 bare conductor running through the conduit replacing the 120 volt line.

Sixty or greater amp 120/240 volt load center with at least 8 regular slots plus 60 or greater amp top breaker set for garage.

Thirty amp GFCI double wide 2 pole breaker in the load center for the pool heater.

Fifteen amp single GFCI breaker for pool pump, rewired to its own circuit.

Fifteen amp single GFCI breaker for chlorine generator, rewired to its own circuit.

Two 15 amp single GFCI breakers for remainders of the the existing 120 volt branch circuits respectively.

At the house panel a 60 amp double wide double breaker to power the new feed to the garage.

Indoor portions of the line run from the conduit to the house panel and from the conduit to the garage load center can optionally be 6-3 NM (Romex) cable with ground with .junction boxes to transition (splice onto) the THWN wires in the conduit.

Another option, have a GFCI breaker as the top breaker of the garage load center and regular breakers for everything else.
 

Last edited by AllanJ; 05-31-17 at 11:53 AM.
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Old 05-31-17, 11:51 AM
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Before anything else we need to know about the existing conduit. Is it plastic or metal? If metal is it threaded or thinwall? If you now have cable, a factory made multiple conductor with continuous overjacket, installed is it type UF or type NM.

If the conduit is thinwall (EMT then it has probably rusted out underground. If the cable is type UF the conduit may not be continuous but only where the cable comes through the surface of the ground. If the cable is type NM and/or the conduit EMT then the whole thing is wrong, probably not installed by a bona-fide electrician, and would need to be replaced.
 
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Old 05-31-17, 12:04 PM
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If the existing conduit is rusted out or not continuous then it will be impossible to pull in the new wiring (using the old wiring as a pull string). You would be dead in the water and have to dig up the yard to put in new conduit or direct bury cable. You might be able to run an overhead feed but I do not know the required specifications for that and also overhead feeds are very unpopular.
 
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Old 05-31-17, 01:53 PM
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Hi all

Currently 2 circuits, each pipe is 3/4 Rigid PVC, contain #12 wire one black, one white and one Green

Now if i am reading this correctly your suggestion is

1. Decommission one 115V circuit
2. Pull 3-#6 wire and 1- #10 wire from the existing 240V outlet from my old AC
3. Install a 100 amp sub panel in the garage with at least 8 breaker slots
4. 8 breaker break down
2 pole 30 Amp GFCI Breaker for Heater
1 Pole 15 Amp GFCI Breaker for Pool Pump
1 Pole 15 Amp GFCI Breaker for SWCG
1 Pole 15 Amp Breaker for LED TV
3 Spare slots
5. Change the breaker in the house panel to two pole 60 amp breaker servicing the existing AC outlet

Is this correct?
 
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Old 05-31-17, 02:12 PM
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1. Decommission one 115V circuit
Two 120 volt circuits were never code compliant. You can not have two circuits to a detached structure. Both 120 volt circuits must be abandoned.
5. Change the breaker in the house panel to two pole 60 amp breaker servicing the existing AC outlet
You could only do that if you had three #6 and one #10 wires going to it of the correct color. You will likely need to come from the breaker box.

At the garage you will need a 100 amp main-breaker panel, at least 12 space. You will need to buy and install a ground bar in it. You will also need at least one ground rod connected to the ground bar of the subpanel with #6 in addition also the (EGC) #10 ground from the main panel and all branch circuit grounds will be connected to the ground bar.. The neutral bar of the subpanel will be isolated.
 
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Old 06-01-17, 02:52 AM
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Is the garage detached?. It is not clear.
 
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Old 06-01-17, 07:57 AM
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Is the garage detached?. It i
Good catch, my bad. It sounded like a detached garage but if my assumption is wrong then ignore my comments.
 
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Old 06-01-17, 08:18 AM
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Yes the garage is detached, I included a pic of the back yard where the house and the garage are detached.

I shouldn't have mentioned it my first post.

Thank you everyone for all the responses.

I am trying to figure out how i am going to get my existing panel to the garage. everything is finished in my basement, and also in my house.


The Air Condition existing outlet, would have be awesome but again that is 240V 20 Amp and probably only #10 wire max, and probably only 3 wire.

The existing circuits will be decommissioned but again just trying to figure from the end of the house to the panel
 
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Old 06-01-17, 09:40 AM
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Is your main panel inside or outside? Do you have an unfinished basement or attic.
 
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Old 06-01-17, 09:47 AM
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Hi

The main panel is in the basement, which is indoors and the basement and upstairs is completely finished.
 
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Old 06-01-17, 11:15 AM
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Presumably the two conduits to the garage come from the panel. You need to verify that. If they are run all the way uninterrupted you may be able to reuse one of them. A " PVC conduit is rated for up to four #6 and you will have three #6 and one #10 so conduit size wise you are okay. The trick will be getting the old wires out and pulling in the new. If the old conduit isn't or you can't get the old out you may still be able to use the inside portion assuming conduit from panel to outside is uninterrupted..
 
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Old 06-01-17, 11:22 AM
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The conduit do not run all the way back to the panel, I was praying they would both conduit start outside the brick house and end at the entrance of the garage
 
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Old 06-01-17, 12:10 PM
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both conduit start outside the brick house and end at the entrance of the garage
So you only need to get to the conduit from the basement. Can you come up from the panel and exit the house?
 
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Old 06-01-17, 12:48 PM
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HI

Yes I can but to get to the garage the conduit will need to be above the ground.

I have attached a layout

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Last edited by ray2047; 06-01-17 at 07:22 PM. Reason: Make diagram easier to see.
  #18  
Old 06-01-17, 03:18 PM
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No good options. I'd suggest fastening new conduit to the outside of the house to the fence and then fasten to the outside of the fence around to the garage or better if possible bury.

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Last edited by ray2047; 06-01-17 at 03:43 PM.
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