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Wire from Disconnect to Panel

czarnik787

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Joined
Dec 28, 2018
Messages
8
Location
Michigan
So moving electrical panel 40 feet from original location. Will be swapping out meter box with meter box and built in 200amp disconnect. My only question is should I buy 2/0,2/0,2/0 copper SER wire and run through joists, or am I able to buy 2/0 THHN through conduit with the conduit through the joists? I know I can’t run thhn through joists but what if it’s in conduit?
 
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wyliesdiesels

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Aug 14, 2012
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20,006
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Modesto, CA
So moving electrical panel 40 feet from original location. Will be swapping out meter box with meter box and built in 200amp disconnect. My only question is should I buy 2/0,2/0,2/0 copper SER wire and run through joists, or am I able to buy 2/0 THHN through conduit with the conduit through the joists? I know I can’t run thhn through joists but what if it’s in conduit?

You need to backup here.

Since you're adding a meter main with disconnect ahead of your current MAIN SERVICE panel where there was no disconnect before, the main service panel now becomes a subpanel which means you CANNOT use 3-wire feeder. You need a 4-wire feeder.

This also means that the neutral bar in the current MAIN SERVICE panel needs to be unbonded and NRTL listed ground bars need to be added. On older obsolete panels, this can prove to be challenging due to parts availability. Any ground wires currently on the now isolated neutral bar will need to be moved over to the new ground bars.

Also, any and all GECs from electrodes and bond wires from water and gas plumbing, water heaters, etc., need to be moved to the bonded neutral bar in the new meter main you put in.

As to your question in green, yes THHN can be ran through conduit in joists. But SER is easier. Personally I would go with AL SER....
 
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czarnik787

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Joined
Dec 28, 2018
Messages
8
Location
Michigan
You need to backup here.

Since you're adding a meter main with disconnect ahead of your current MAIN SERVICE panel where there was no disconnect before, the main service panel now becomes a subpanel which means you CANNOT use 3-wire feeder. You need a 4-wire feeder.

This also means that the neutral bar in the current MAIN SERVICE panel needs to be unbonded and NRTL listed ground bars need to be added. On older obsolete panels, this can prove to be challenging due to parts availability. Any ground wires currently on the now isolated neutral bar will need to be moved over to the new ground bars.

Also, any and all GECs from electrodes and bond wires from water and gas plumbing, water heaters, etc., need to be moved to the bonded neutral bar in the new meter main you put in.

As to your question in green, yes THHN can be ran through conduit in joists. But SER is easier. Personally I would go with AL SER....


I hear ya, I knew that just didn’t type it and the ground bars are already in place, ser is easier you are right but I could get better deal on THHN so I was curious thank you.
 

wyliesdiesels

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Aug 14, 2012
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Modesto, CA
I hear ya, I knew that just didn’t type it and the ground bars are already in place, ser is easier you are right but I could get better deal on THHN so I was curious thank you.

Will you be unbonding the neutral bars as well?

What brand and model of panel do you have?

Do you have some pics of the panel with the cover off?
 
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czarnik787

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Dec 28, 2018
Messages
8
Location
Michigan
Will you be unbonding the neutral bars as well?

What brand and model of panel do you have?

Do you have some pics of the panel with the cover off?

I’ll unbond the neutral as sub panel will have separate neutral and ground. My house was built before code was implemented for grounding rods to be added in foundation and plumbing is plastic, so two grounding rods are added exterior which two new ones will be placed in new panel location area exterior. So my current panel is Siemens 200amp. So I will un bond the neutral run a separate neutral wire with my two hits and then ground will come from the grounding rods and tire into grounding bud bar in panel.
 

wyliesdiesels

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Modesto, CA
I’ll unbond the neutral as sub panel will have separate neutral and ground. My house was built before code was implemented for grounding rods to be added in foundation and plumbing is plastic, so two grounding rods are added exterior which two new ones will be placed in new panel location area exterior. So my current panel is Siemens 200amp. So I will un bond the neutral run a separate neutral wire with my two hits and then ground will come from the grounding rods and tie into grounding bus bar in panel.

That's incorrect. As i said, you need a 4-wire feeder between the meter main and subpanel(current main service panel).

The ground rods do not establish a low impedance fault current pathway. The GEC wire from the ground rods need to go to the meter main NOT the subpanel.
 
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czarnik787

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Dec 28, 2018
Messages
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Michigan
That's incorrect. As i said, you need a 4-wire feeder between the meter main and subpanel(current main service panel).

The ground rods do not establish a low impedance fault current pathway. The GEC wire from the ground rods need to go to the meter main NOT the subpanel.

Again all I told you is what is going to the new panel the meter box will now acquire the two already in place grounding rods feeding the panel in place now.
 
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czarnik787

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Joined
Dec 28, 2018
Messages
8
Location
Michigan
That's incorrect. As i said, you need a 4-wire feeder between the meter main and subpanel(current main service panel).

The ground rods do not establish a low impedance fault current pathway. The GEC wire from the ground rods need to go to the meter main NOT the subpanel.

Realized I stated that in a crude way �� didn’t mean too and my previous post did not state two new grounding rods just said grounding rods my bad ��
 

Norcal

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Mar 16, 2008
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13,754
Is this a house or shop panel? Reason I ask is the use of 2/0 CU for 200A.
 

teamextreme

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Lakewood, CO
So I will un bond the neutral run a separate neutral wire with my two hits and then ground will come from the grounding rods and tire into grounding bud bar in panel.

This is what wylies is concerned about, and rightfully so. You state you are running 2 hots and a neutral and the ground will come from the ground rods. That is a 3-wire feed and is not allowed. You will not have an effective low impedance ground fault path with this arrangement and would be very dangerous. You need 4 conductors from the new meter/main to the existing panel.
 

wyliesdiesels

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Modesto, CA
This is what wylies is concerned about, and rightfully so. You state you are running 2 hots and a neutral and the ground will come from the ground rods. That is a 3-wire feed and is not allowed. You will not have an effective low impedance ground fault path with this arrangement and would be very dangerous. You need 4 conductors from the new meter/main to the existing panel.

yeah his description leaves doubt in my mind.
 
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