Ask Me Help Desk - Adding subpanel for basement workshop

Hi -
I have 200 amp service to my home and would like to add a workshop in the basement with a separate subpanel. The run from the main to the sub will be short (< 10 ft) so voltage drop should not be a problem.

I have been advised to take 240v. via a dual pole 30 amp CB from the main to the sub and then two or three circuits off the sub to various junction boxes for the tools (table saw, chop saw, power vac. Etc ). Lights are on a separate circuit from the main panel.

First off does this sound like a good plan? What wire size would you use for the run?

Thanks in advance for your help

SSB

Plan sounds modest and reasonable. Use 4 wire #10 cable with a green or bare ground.

Be sure to keep the neutral insulated from the metal case of the panel, and connect all grounds to a ground bar mounted directly to the metal case.

Quote:

Originally Posted by tkrussell

Plan sounds modest and reasonable. Use 4 wire #10 cable with a green or bare ground.

Be sure to keep the neutral insulated from the metal case of the panel, and connect all grounds to a ground bar mounted directly to the metal case.

Modest? Do you think more power is in order (i.e. 40-60 amp)?
Also, does the subpanel need to be grounded separately (i.e. to it's own rod) or can it be grounded to the ground in the main?

Thanks again for your expertise

Quote:

Originally Posted by ssb

Hi -
I have 200 amp service to my home and would like to add a workshop in the basement with a separate subpanel. The run from the main to the sub will be short (< 10 ft) so voltage drop should not be a problem.

I have been advised to take 240v. via a dual pole 30 amp CB from the main to the sub and then two or three circuits off the sub to various junction boxes for the tools (table saw, chop saw, power vac. etc ). Lights are on a separate circuit from the main panel.

First off does this sound like a good plan? What wire size would you use for the run?

Thanks in advance for your help

SSB

I'd probably put a 60 amp breaker in the main panel. You would need 6/3 or 8/3 copper with ground. Neutral and ground are not connected together in the sub-panel. The sub-panel does not need a main breaker

Here is a thread as to how not to do it: https://www.askmehelpdesk.com/electr...re-122146.html

I posted this link in that thread for a good overview:

Adding New Electrical Circuits - Installing A Sub-Panel - An Overview

Something to think about while wiring the shop is what might be necessary for a central dust collecting system. If you plan for separate circuits, you can easily place current sensors in the panel or a separate panel that would turn on the vacuum when the power tool was turned on. SSAC, ABB SSAC Timers & Controls Fast Facts (800) 377-SSAC(7722) makes some nice sensors. An example: http://www.ssac.com/catalog/ECS01A01.pdf

What I would envision is a separate NEMA 1 enclosure where the wires would initially enter and then a large conduit like 2" or so connecting to the Breaker panel. They would enter into the NEMA 1, go through the current sensor and on to the breaker. Nice, clean, simple and add sensors as you need to.

It's something to think about. It's much easier to do it now than add later.

Quote:

Originally Posted by KeepItSimpleStupid

I'd probably put a 60 amp breaker in the main panel. You would need 6/3 or 8/3 copper with ground. Neutral and ground are not connected together in the sub-panel. The sub-panel does not need a main breaker

Here is a thread as to how not to do it: https://www.askmehelpdesk.com/electr...re-122146.html

I posted this link in that thread for a good overview:

Adding New Electrical Circuits - Installing A Sub-Panel - An Overview

Something to think about while wiring the shop is what might be necessary for a central dust collecting system. If you plan for separate circuits, you can easily place current sensors in the panel or a separate panel that would turn on the vacuum when the power tool was turned on. SSAC, ABB SSAC Timers & Controls Fast Facts (800) 377-SSAC(7722) makes some nice sensors. An example: http://www.ssac.com/catalog/ECS01A01.pdf

What I would envision is a separate NEMA 1 enclosure where the wires would initially enter and then a large conduit like 2" or so connecting to the Breaker panel. They would enter into the NEMA 1, go through the current sensor and on to the breaker. Nice, clean, simple and add sensors as you need to.

It's something to think about. It's much easier to do it now than add later.

Thanks for the ideas on the current sensors and the overview link...