Exhausted "Search" looking for Sub Panel Feeder Routing Advice

[StumpFJ40]

I've exhausted the Google machine and the GJ search function, with no real answers to my particular conundrum.

I am in the process of purchasing a home that will allow me to build an additional attached garage that will be my dedicated auto workshop.

Issue: I will (obviously) need dedicated power in the workshop. My plan is for a 240V/90A supply using 2-2-2-4 Aluminum SER. The shop will have lighting, many 120v/20A outlets, a 240v/20A outlet for a 60gal 5hp compressor, 3-4 240v/50A outlets for a Hobart 210 welder, plasma cutter/TIG machine (not run simultaneously), 120v/20A outlet for fan for propane ceiling mounted heater, and power for a 2 post lift.

Situation: The electric service entrance and the 2 main boxes is in the basement on the opposite side of the house. I am assuming, based on the home's build date (2005) and it's size, that the service is either 300A or 400A. I don't know why they would run 2 boxes for 200A service. BTW, each box has only a hand full of breakers in each.

It is a 70-ish foot run from one end to the other through the basement ceiling, based on my routing plan. A good portion of the route would be through finished sections of the basement. (amateur sketch below, for reference)

Questions:
Is 2-2-2-4 the right choice based on my shop general power requirements?What are this requirements for routing SER through a finished ceiling space? I assume no insulation and I also assume a good portion, if not all, may be perpendicular through the joists. There also may be areas where I run parallel to the ceiling joists

In the perpendicular runs, I want to get more towards the centers of the joists. Wouldn't I also need to install nail plates where the cable runs through each joist?

For the parallel runs (this is where I couldn't find a definitive answer) am I required to secure the cable to the joist, or can it lay on the drywall in the joist bay? As I (non-professional) interpreted Article 334 of the NEC, when SER cable is run inside a single family residence, the SER cable is to be treated like NM wire. And there is nothing in the NEC, that I could find, that specifies how NM should be secured when running through finished ceiling or floor joist bays. I certainly never secured 12AWG Romex when installing recessed lights in an existing ceiling.

All and all help, advice, comments, or criticisms are welcome.



Thanks in advance!

Cheers,
Stump

 

[pattenp]

NM can be run through spaces where it's not accessible to be secured, so the SER can just be pulled through the joist cavity without having to be secured within the cavity. Any cable going through bored hole must be at least 1.25" back from the nailing surface or if less than 1.25" protection plates must be used

 

[wyliesdiesels]

The 20a outlet will NOT work for a 5HP motor.

If you want an outlet, you will need to use pin and sleeve connectors because standard nema outlets and plugs are not rated for more than about 3HP.

Those are expensive so your other option is to hardwire it.

If it will be more than 50’ from and not within sight of the breaker panel you will need a disconnect as well.

 

[StumpFJ40]

NM can be run through spaces where it's not accessible to be secured, so the SER can just be pulled through the joist cavity without having to be secured within the cavity. Any cable going through bored hole must be at least 1.25" back from the nailing surface or if less than 1.25" protection plates must be used

Thank you for the confirmation and the info regarding the plates.

 

[yatg]

The 20a outlet will NOT work for a 5HP motor.

Depends on if its a 5HP "peak" or 5HP actual.
If it has a factory cord and plug on it, you're probably good.
Otherwise post a picture of the motor nameplate.

 

[wyliesdiesels]

Depends on if its a 5HP "peak" or 5HP actual.
If it has a factory cord and plug on it, you're probably good.
Otherwise post a picture of the motor nameplate.

Im only referring to 5HP nameplate listed motors. HP rating is what is required to size a motor circuit.

The NEC does not use the terms peak or actual. Its all about what the nameplate says. Since the OP said 5HP, Im using that figure

 

[SGKent]

based on what you are going to create, and the expense involved with those dreams, there will be an architect involved - especially because it is attached to the main dwelling. Homemade plans rarely work for projects like that. Depending on how much work you do in this attached shop, the fire marshal may have to sign off on it too. I'd start lining up contractors whom you want to deal with including an electrician, unless you are just going to hire a GC to do the work. Between the architect and the electrician they can figure it out. All you need do is set the money aside for the project.

 

[StumpFJ40]

The 20a outlet will NOT work for a 5HP motor.

If you want an outlet, you will need to use pin and sleeve connectors because standard nema outlets and plugs are not rated for more than about 3HP.

Those are expensive so your other option is to hardwire it.

If it will be more than 50’ from and not within sight of the breaker panel you will need a disconnect as well.

Depends on if its a 5HP "peak" or 5HP actual.
If it has a factory cord and plug on it, you're probably good.
Otherwise post a picture of the motor nameplate.

I just took some snaps. It is an older CH Professional 60 gal I bought while stationed in Canada.

 

[StumpFJ40]

I just took some snaps. It is an older CH Professional 60 gal I bought while stationed in Canada.
It says 5HP, but 15A. Clearly 5 peak HP.

 

[StumpFJ40]

Sorry for the double-ish post... this forum engine doesn't like google photo links.

 

[wyliesdiesels]

It says 5HP, but 15A. Clearly 5 peak HP.

Actually it just says 5. I dont see HP anywhere on the label.

15a FLA is about 3HP. so youre fine with a plug and outlet

 

[AntonLargiader]

Actually it just says 5. I dont see HP anywhere on the label.

15a FLA is about 3HP. so youre fine with a plug and outlet

At 240?

 

[StumpFJ40]

Actually it just says 5. I dont see HP anywhere on the label.

15a FLA is about 3HP. so youre fine with a plug and outlet

At 240?

Simple motor hp calculation (240*15)/746 comes to 4.8 hp. I have no problem hardwiring it in, though for the last 13 years, I’ve ignorantly been running it with a 240v/20a plug, with no issues.
Thanks for the information.
I’m here to learn.

 

[u2slow]

I just took some snaps. It is an older CH Professional 60 gal I bought while stationed in Canada.
It says 5HP, but 15A. Clearly 5 peak HP.

My ~10cfm portable compressor draws 16amps FLA @ 240V. It came with a factory 6-20P cord.

Your Hobart 210 should run fine on a similar 20A circuit.... my Millermatic 211 does. I made a short cheater cord to adapt it.

I also ran #2 AL to my shop. Probably overkill. I didn't ever trip the previous #8/40A temporary feed.

 

[wyliesdiesels]

At 240?

Yes go look at NEC FLC table 430.248

3HP is listed as 17a. Ive never seen a 3HP that high. 3HP motors are typically 13-15a

Simple motor hp calculation (240*15)/746 comes to 4.8 hp. I have no problem hardwiring it in, though for the last 13 years, I’ve ignorantly been running it with a 240v/20a plug, with no issues.
Thanks for the information.
I’m here to learn.

746watts per hp is 100% efficient. In the real world that is not the correct figure to use.

If you look at table 430.248 you will see that 3HP is 17a.

 

[Bert_]

This^

Simple motor hp calculation (240*15)/746 comes to 4.8 hp. I have no problem hardwiring it in, though for the last 13 years, I’ve ignorantly been running it with a 240v/20a plug, with no issues.
Thanks for the information.
I’m here to learn.

That assumes 100% efficiency and power factor. No motor ever made meets that criteria.

Most single phase motors are 70-80% efficient and maybe 85-90% power factor at full load.