Need to add on electrical service
 

I have a 200 amp eaton br serries main panel.
The bottle neck is a 1.25 inch conduit that goes across the back of the house that is unbelievably over stuffed.
Originally I believe the only thing in that conduit was the air conditioning power and the range power.
Now its servicing: central air, electric range, shed, 120v 30 amp power for the garage and improper wire going to the out building.
Need to keep that and add up to 100 amps worth of welder power for my miller dialarc, a 240v electric car charger, solar power inputs, 240v power out to the shed and well pump power.
So I was thinking I would remove the junction box, pull all those wires back out install a QO 125 amp 24 circuit outside panel where the junction box was. Put a 125 amp breaker on the eaton main, run 2 gauge wires through the 1.25 inch nipple, then add a conduit or 2 to the sub panel to relieve the over stuffed 1.25 conduit condition put the new stuff in its own conduit.
I might leave 1 or 2 circuits going back to the main but that might over fill my 1.25 sub to main conduit more than 40%.
An electrician would want a few thousand to do this.

Depends on what materials yu can get at low cost.

A firend in NM is near Hollman AFB, get used Cu wire and conduit for scrap prices.

If you have similar situation, would simply run a parallel 2" conduit with as big a wire as you can find surplus.

Don't forget about voltage drop, although not too important for the welder. I run a 320 Amp buzz box off 130 ft of 8 AWG run out to the barn and only trip the 50A breaker if I run a high duty cycle for over 15 minutes at full amp setting but likely getting under 300A at rods.

Yeah I have a huge hordes of 2,4, 6, 9 and 10 gauge thhn wire bought from scrap yards. I have some 1, 0 and 00 gauge. Also have a lot of 12/2, 10/2 and 10/3 romex. Actually the other day I realized I had ran out of 12/3 with ground romex and had to buy more at retail prices. Not cool.
This is one of the ways I am going to put in solar so cheaply. I won't have to buy any wire.

Yesterday I got about about 30 feet of 12/3 stw (thermo plastic extension cord) from the scrap yard to make my self a nema 6-20 cord for charging my leaf. It cost $12. If I had bought new sj cable it would have cost around $70.
All I have to do is put ends on it.
Miller recommends putting the model 250 on a 100 amp circuit.
Which would allow me to run 6 gauge on a 100 amp circuit as long as it's only for the welder. I will probably use 4 gauge and make it a 125 amp circuit, to eliminate nuance trips while welding aluminum.

We use 2" conduit for 200 amp and 1-1/4" for 100 amp .

Wyr
God bless

It turns out it's 1.5 inch going through the wall. Then 1.25 along the wall.
I was looking at the conduit fill chart and noticed 1.25 inch for 125 amp service was not really ideal. But 1.5 leaves plenty of room.

Maybe it's just me, but I'd pay retail for some aluminum service cable before I'd run several dozen feet of free conduit through an attic and then fight with pulling free >6ga wire through it. That's cardio I can do without. :-)

Charlie

The conduit is on the back side of the house.
I will likely run 4 gauge to my big welder.
Probably run some 6 gauge in conduit out to the garage to run dryer, air compressor, electric vehicle charger, lights, garage doors and such.

I'm going to run power to my welder on a dedicated circuit off the main with a 125 amp breaker on 4 gauge wire.
Since I have nearly unlimited 4 gauge wire.

# 4 copper ?

Wyr
God bless

I only do copper.

For residential work , I would normally use a 100 amp CB for # 4 copper . Not a 125 amp CB .

Wyr
God bless

I only run copper around here because the inspectors take an extra close look at any aluminum wiring that runs inside finished walls. They get out their box and start doing calculations and stuff.
If they saw 4ga on a 125 amp breaker they may not even bother to question it.

This is for a dedicated welder circuit.
NEC 630.11 I think is the one.
Because welders are intermittent variable loads, depending on the welding machines I could as much as double the breaker size over what's normally installed on a given wire size.
I could go as little as 6 gauge on a 100 amp breaker.
But I run my welding circuits to be at least 50% duty cycle for the wire size. Running my miller model 250 which is about out the size of an apartment refrigerator and weighs 360lb, at full power draws about 100 amps. 100 amps on 4 gauge wire is about a 80 or 90% duty cycle. My welder is rated for a 40% duty cycle at full power. If some how I ran the full 125 amps on that 4 gauge line it would be good for about a 60% duty cycle.
A welding machine that would draw 125 amps at a 60% duty cycle would be a machine about 2 class sizes bigger than what I have now. Those welding machines are typically used to build bridges, skyscrapers, power plants, ships, oil rigs.

When I move I will pull the 125 amp breaker off that welder circuit and put in an 80 or 90 amp breaker and relabel it "electric vehicle charger ".

When I installed our electric vehicle charger for our Nissan Leaf ( that we had before it got run into and totaled ) , I ran # 6 copper & put it on am 2 pole 40 amp CB . It was fused , internally , with 40 amp fuses .

We run only copper .

Wyr
God bless

My hard wired charger will likely be 8 gauge ran on a 40 amp breaker also. I have the slow charging 2011 leaf, it will only draw 16 amps max with my after market 3.8kw charger. That 40 amp circuit will be incase I upgrade to a vehicle and charger that can do 6.6kw charging.
My other EVSE is the original 12 amp nissan brick charger converted to 240v by me.

I could have used # 8 Romex , but I had # 6 left over from another job .

I installed the GE Wattstation . It was just about the cheapest " full power " level 2 device I could find .

Ours was a 2012 Leaf . Still with the 3.8 kw charging rate , also .

Wyr
God bless

Did you ever amp clamp that 2012 leaf while charging?

I do not think so . At least I can not remember doing so .

Wyr
God bless

What size / amperage circuit breaker ?

Wyr
God bless

My main charging circuits at home are two seperate 20 amp, 12/3 with ground romex cables going to 6-20 amd 5-20 combination duplex receptacles. That way when I'm not charging I can use them for any normal 120v activity.
Then I have 30 and 50 amp RV circuits at my away locations. They are dedicated circuits that run outside to an RV box with a L14-30, 10/3 with ground and a 30 amp breaker.
The one 14-50 is wired on 50 amp with 6 gauge, so my buddy can use his little stick welder.

Then if 20 amp circuits become too small my welding circuit at home is ran on 4 gauge so it can handle anything.
I could charge like 6 cars at my house if most of them used 12 or 16 amp evse chargers.