Maximum Amperage Draw

[Guest]

No doubt. Copper is better. But aluminium can be installed safely/correctly as well. Not sure what you mean by 'Aluminium creeps'?

Scott,

My understanding is that as aluminum (if not installed correctly, NAOLOX etc) will oxidize and as resistance rises, the aluminum can expand when the material heats up. This will deform the material (creep) at the connection and when it cools the connection will become loose. Rather than dealing with someone that I have to assume I can trust with aluminum, I felt far more confident with his use of copper.

Jim

[Scott'n'Wendy]

Ah yes. I've never heard it called 'creep' before, but I understand you now.
When running house services in the past, I quoted 4/0 aluminium or 2/0 copper for 200A. I'm talking over ten years ago and AL was a lot cheaper then as well.
But try buying some AL bar stock or square tubing..It isn't cheap in that form!!

[Guest]

Ah yes. I've never heard it called 'creep' before, but I understand you now.
When running house services in the past, I quoted 4/0 aluminium or 2/0 copper for 200A. I'm talking over ten years ago and AL was a lot cheaper then as well.
But try buying some AL bar stock or square tubing..It isn't cheap in that form!!

Scott,

I don't want to take us into the weeds but whats your opinion of a 200amp AL main in a home built in 1999? Any recommended maintenance on those lines?

If I were wiring a campground style pedestal outside and all the AL was outside, I would not care.

Jim

[gbkims]

My 1990 house has buried aluminum service conductors from a pad mount transformer to the service, at least that's what comes out of the meter can next to the 125A load center that's on an outside south wall..
I can see there was a compound (noalox?) applied to the aluminum wires at the main lugs.
I've put a screwdriver on the lugs once or twice over the years to see if I could feel any loosening. Never been loose

The wire markings 1/0 Compressed AL 600V XLP Type USE (2), Neu= 2 AWG Compressed AL 600V XLP Type USE, make them look like 1/0-1/0-2 Brenau Triplex Aluminum Conductor Underground Direct Burial 600V URD
Compressed aluminum is apparently an alloyed aluminum wire - https://www.ecmweb.com/content/artic...-building-wire

One phase pulls a bit more amps than the other with normal house loads, even after seeing if I could balance the loads.
This morning:
16.905 Amperes Circuit Breaker Panel - Amps L2
28.178 Amperes Circuit Breaker Panel - Amps L1

IR photo from July 2019, Ambient of 90°F


IR photo April 2021 The most load I'd noticed, I was doing some testing.
54.665 Amperes Circuit Breaker Panel - Amps L2
44.065 Amperes Circuit Breaker Panel - Amps L1

[TedS]

All aluminum wire is alloyed aluminum. Pure aluminum is not used. It would not have the strength properties required.

Aluminum wire is compressed the reduce its diameter and compact the strands.

[Guest]

My 1990 house has buried aluminum service conductors from a pad mount transformer to the service, at least that's what comes out of the meter can next to the 125A load center that's on an outside south wall..
I can see there was a compound (noalox?) applied to the aluminum wires at the main lugs.
I've put a screwdriver on the lugs once or twice over the years to see if I could feel any loosening. Never been loose

The wire markings 1/0 Compressed AL 600V XLP Type USE (2), Neu= 2 AWG Compressed AL 600V XLP Type USE, make them look like 1/0-1/0-2 Brenau Triplex Aluminum Conductor Underground Direct Burial 600V URD
Compressed aluminum is apparently an alloyed aluminum wire - https://www.ecmweb.com/content/artic...-building-wire

One phase pulls a bit more amps than the other with normal house loads, even after seeing if I could balance the loads.
This morning:
16.905 Amperes Circuit Breaker Panel - Amps L2
28.178 Amperes Circuit Breaker Panel - Amps L1

IR photo from July 2019, Ambient of 90°F


IR photo April 2021 The most load I'd noticed, I was doing some testing.
54.665 Amperes Circuit Breaker Panel - Amps L2
44.065 Amperes Circuit Breaker Panel - Amps L1

Gene,

This is an awesome post where I need to rent one of those IR cameras. They rent them at some HD stores where I was looking to do an energy audit where I've sealed off my crawl space and installed a commercial grade de-humidifier to make this a conditioned space. An IR Camera would be helpful in checking for RV issues as well.

Curious, how would you balance the loads between L1 and L2?

Jim

[Scott'n'Wendy]

Aluminum wire is compressed the reduce its diameter and compact the strands.

So is copper.

Guest
A house where the main incoming is aluminium would not concern me. Going to the meter base and checking torque could be done pre-purchase I suppose, but would have to get involved with the supply authority.
The 'creep' as you refer to it does not manifest itself with house incoming wires. The reason being a house never pulls the 200A the incoming cable is rated for so it doesn't heat up and expand like a 14ga wire feeding a receptacle that could. A receptacle could easily see near max load. A hair dryer would do it or a microwave, a coffee maker....
Which is probably why gbkims never found a loose lug.

[gbkims]

Gene,
...
Curious, how would you balance the loads between L1 and L2?

Jim

Jim,

I looked at typical amps usage on the various room CBs with a clamp on ammeter.
Then tried swapping a couple of 120V circuits to different CBs that are on one of the other Load Center phases.
I was seeing if I could get the loads on L1, L2 close to each other most of the time.

9.981 Amperes Circuit Breaker Panel - Amps L2 - 2:32:04 PM
5.381 Amperes Circuit Breaker Panel - Amps L1 - 2:32:04 PM
---
5.612 Amperes Circuit Breaker Panel - Amps L2 - 2:34:55 PM
5.132 Amperes Circuit Breaker Panel - Amps L1 - 2:34:55 PM
--
13.100 Amperes Circuit Breaker Panel - Amps L2 - 2:38:15 PM
17.604 Amperes Circuit Breaker Panel - Amps L1 - 2:38:15 PM

Today I'm looking at my house A/C (Carrier Scroll + TXV) to see how large the Inrush Amps are with its originally installed 5-2-1 hard start potential relay + capacitor..kit.
Startup amps on my regular clamp meter showed 32.7A RMS Max. Running amps are ~10A RMS
My old 345 PQ showed higher peak amps (+179.6A, -214A) for about 4 cycles of 60Hz.


I took some screen shots of my 240v at the Load Center. Interesting to see how much distortion of the current there is by the appliances and electronics in the house.

[Guest]

So is copper.

Guest
A house where the main incoming is aluminium would not concern me. Going to the meter base and checking torque could be done pre-purchase I suppose, but would have to get involved with the supply authority.
The 'creep' as you refer to it does not manifest itself with house incoming wires. The reason being a house never pulls the 200A the incoming cable is rated for so it doesn't heat up and expand like a 14ga wire feeding a receptacle that could. A receptacle could easily see near max load. A hair dryer would do it or a microwave, a coffee maker....
Which is probably why gbkims never found a loose lug.

Thank you Scott.

Jim

[TheNescios]

I'll echo the opinion that aluminium is decent for feeder circuits - and the oxidization can be dealt with by using a healthy amount of de-ox that's formulated for just this application.
Think the "creep" being referenced might reference the reason aluminium was discontinued for overall wiring applications - from what's in my memory bank it had to do with how it expanded & contracted under load vs copper in receptacles & switches, over time not making as good a connection which led to issues. Feeder and branch circuits typically have better connecting mechanisms for the wire so hence very few issues if installed correctly.
Keep in mind my mind isn't what it used to be so this information might not be as accurate as I hope it is??
Chris

[Guest]

I'll echo the opinion that aluminium is decent for feeder circuits - and the oxidization can be dealt with by using a healthy amount of de-ox that's formulated for just this application.
Think the "creep" being referenced might reference the reason aluminium was discontinued for overall wiring applications - from what's in my memory bank it had to do with how it expanded & contracted under load vs copper in receptacles & switches, over time not making as good a connection which led to issues. Feeder and branch circuits typically have better connecting mechanisms for the wire so hence very few issues if installed correctly.
Keep in mind my mind isn't what it used to be so this information might not be as accurate as I hope it is??
Chris

Chris,

This is my understanding where I've learned about the aluminum main coming into the load center from folks here and feel much better about it. However, when having a line added to power a 230V 50amp outdoor appliance I'm happy in my choice of copper. Trust or the lack of it is why I feel comfortable in that decision.
If I were building the home, I would still insist on copper inside the home but for the AL main I have, I can live with it after receiving input from folks here that are in the industry.

Thanks to everyone,

Jim

[TheNescios]

Jim,
Important part is to be comfortable with the choice of materials for your project - we all have preferences and it's the reason when we go to the stores there is more than a few choices for most things?
Good part is how the people on the forum were able to help!
Chris