Load center, power distribution

[Julio Navarro]

What sort of power arrangement does your shop have?

Which is the best set up as far as a load center, cut off switches, receptacles?

Does each machine have a dedicated circuit?

I am thinking about running a load center off the main panel (home type circuit) Putting at least one 240v 30 amp circuit for the cyclone DC and the rest dedicated circuits for the rest of the machines. Maybe leave two spaces for a future 3 ph cicuit in case I need on in the future.

The lighting I figure I would leave on the existing circuit as it is very minimal, 3 flourescent/2 bulb 4ft hanging lamps.

I would need shut off switches so I could disconnect each machine individually and maybe a main shut off ahead of the load center to keep everything off when I am not there, maybe have a lock on it for safety.

[Ken Fitzgerald]

Julio.........I am in the process of finishing my new shop. I installed a meter base and I installed a Square D panel.....not the home owner series but their commercial series....200 amp 240 v panel. I have dedicated circuits for the Dc, the air compressor. I have 4 120 circuits that the feed the wall outlets. I have 9 240 wall outlets, each on their own breaker. I have 2 circuits for lighting. I have a 40 breaker box and all but 2 slots are being used. I left those 2 in case I want to install a special outlet for an arc welder.

[Mike Henderson]

Julio, You don't say whether your shop is a home shop or a commercial shop. If it's a home shop, and you're the only person in the shop, you can do things differently than if you have a commercial shop with several people working in it.

If you're asking about a home shop, and you're the only person working in it, you will generally only be using one tool at a time so you won't need a high amperage service.

For example, when I built my home shop, I put in a sub box at my shop with a 50 amp breaker in my main box supplying the sub box. From the sub box I ran a couple of 220 circuits and the rest 20 amp breakers for 110 volt outlets. I ran a number of circuits and spread the outlets over the shop so that no two adjacent boxes are on the same circuit. The only problem with dedicated circuits is that you'll re-arrange your shop and then you'll have a bunch of electrical work to do with the re-arrangement. For 110 volt tools, just use the standard outlets. For 220 volt tools, you will need dedicated cricuits.

I also put my lights on GFCI just to be safe.

One additional suggestion is to have a switch box for your air compressor so that you can turn it off when you leave the shop.

And if it's a home shop, I doubt if you're going to be able to get three phase service.

Mike

[Barry O'Mahony]

Julio, the main cutoff switch is a good idea, especially if you have kids around.

My shop has its own service main panel, which has feeders going to a couple of other outbuildings. Light, heat, and a couple of receptacles for the refrigerator and battery chargers come off the main. Everything else (all other receptacles, and power tool dedicated circuits) are off a subpanel. The subpanel feeder goes through a 60 amp switch, the kind with the big red handle that can be padlocked in the Off position. You can get these on eBay or elsewhere for not too much. This is padlocked when I'm not around. As a reminder, I have a red light bulb that is powered up when the switch is turned on.

You can use the breakers themselves as disconnect switches for the machines. If the machines are hard-wired (no plug), then the breakers must be within sight of the machines in order to serve as the "disconnecting means" required by the NEC.

[tod evans]

julio, i believe in a dedicated panel for the shop, square "d" qo type, not the homeline stuff..i`m also a firm believer in oversizing wire by one gauge for the circuit and i have installed fused disconnects at my larger equipment....02 tod

[Rob Russell]

And if it's a home shop, I doubt if you're going to be able to get three phase service.


Mike,

I think you'll find that Julio is talking about leaving space in his single-phase panel for a 240v breaker to feed a phase convertor of some sort (rotary phase convertor, Phase Perfect, VFDs, etc.)

Rob

[lou sansone]

answer to your questions

1. separate 3 phase power to shop - 400 amp feeder with 200 amp main breaker

2. 48 circuit load center

3. large machines have their own circuit

4. smaller machines share circuits

5. conduit throughout - no romex

6. lots of 20 amp 120 volt circuits for hand tools and such

7. lighting on separate circuits

best wishes
Lou

[Julio Navarro]

hmmm, now thats got me thinking.. I thought 3 pole meant 3 phase?? (shows how much I know)

Heres the motor I need to run for the DC (shakes my head shamefully)http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=7570 it says split phase, not sure what that is.

Why use Square D "Q" panels, the darn breakers are twice the cost of the Homeline ones. Obviously price reflects quality in this case, but is the Homeline that bad?

I was thinking of using a 6 space 12 circuit load center and use two for the 3 pole motor, the rest I would distribute to the shop. I had thought of using the homeline panel but from the responce here I am guessing its not a good idea.

I want to put a cut off switch at each machine (red handle and lock) my son is starting to show an interest in my woodworking and I am affraid he might get adventurous despite my repeated and dire warnings about even being in the shop with out me. Not to mention if he brings in a friend!

I can put two machines per circuit but I would be pretty much limited on future expansion I suppose.

[Rob Russell]

What sort of power arrangement does your shop have?

Which is the best set up as far as a load center, cut off switches, receptacles?

The suggestion of a locking master switch that allows you to kill all of the machinery/tool circuits is a good one. I’d suggest having some sort of 120v circuit near your subpanel that is powered from your main panel so you have the ability to run a shop vac or drill on an extension cord (for installing all your electrical stuff) even if your master panel is locked. Remember that the NEC requires illumination by your subpanel, so if you don’t have a light right where you’ll be installing the shop’s panelboard, you’ll need to install a light. You’d want one anyway.

In terms of “cut off switches”, if you’re talking about disconnect switches for your machines, I wouldn’t go that route. As anal as I am about over-engineering stuff, a cord-and-plug connection is an NEC-approved disconnect. In my mind, it’s safer to unplug a machine and drape the cord over it when you’re changing blades/cutters than it is to have a switch that you throw. It seems easier to me to become complacent about switches, but unplugging a machine is one of those obvious things – either the cord is plugged into the wall or it’s draped over the machine you’re working on. If you go the cord-and-plug route, I’d recommend using twistlocks. eBay is a good source for things like that, if you’re patient. I bought all my Hubbell plugs and receptacles online for significantly less than I could have bought them at the local electrical wholesaler (I have an account there).


Does each machine have a dedicated circuit?

I am thinking about running a load center off the main panel (home type circuit) Putting at least one 240v 30 amp circuit for the cyclone DC and the rest dedicated circuits for the rest of the machines. Maybe leave two spaces for a future 3 ph circuit in case I need on in the future.

It’s not an NEC requirement that we run dedicated circuits for our machines. You could, for example, run (4-6) 15 or 20 amp 240v circuits around your shop with multiple receptacles on each circuit. Simply balance the circuits by plugging your machines into different circuits. That way, if you decide to move a machine, you move it and plug it into one of the receptacles in the new location. If you want to run multiple machines simultaneously, simply plug them into different circuits.

You certainly can run dedicated circuits if you want to. That's your choice.



The lighting I figure I would leave on the existing circuit as it is very minimal, 3 flourescent/2 bulb 4ft hanging lamps.

This is actually a very safe approach. It means that, if something happens mid-cut and the main breaker feeding your machinery subpanel trips, you're not left in the dark. Depending on how safety-conscious you are, you could also install a battery powered emergency floodlight so if the power goes out when you're mid cut, you at least have light to see what's going on as the machine is winding down.

If your shop is in your basement, remember that the 120v circuits must be GFCI-protected.

Speaking of safety, don't forget fire extinguishers.

Rob

[tod evans]

julio, i`m not an `lectrition! but please call any of your local guys and ask them why to use the qo series.....i just listen to the guys who jerk wire for a living and haven`t had any troubles...02 tod

[Julio Navarro]

Speaking of safety, don't forget fire extinguishers.

Rob

Excellent idea, hadn't thought about that!

[Rob Russell]

hmmm, now thats got me thinking.. I thought 3 pole meant 3 phase?? (shows how much I know)

3-phase means 3 HOT legs. That means running either 3-phase service to your house or a phase convertor to generate the extra hot leg. 3-phase power is really only a factor if you start getting into bigger machines (7.5HP or higher) or want to buy industrial machines that have 3-phase motors in them.


Why use Square D "Q" panels, the darn breakers are twice the cost of the Homeline ones. Obviously price reflects quality in this case, but is the Homeline that bad?

The QO series uses a copper bus instead of aluminum and the breakers have a positive (red flag) indicator when they trip.


I was thinking of using a 6 space 12 circuit load center ...

That's way too small. I wouldn't put in anything smaller than a 20-slot panelboard.


I want to put a cut off switch at each machine (red handle and lock) my son is starting to show an interest in my woodworking and I am affraid he might get adventurous despite my repeated and dire warnings about even being in the shop with out me. Not to mention if he brings in a friend!

A single locking disconnect switch for the whole electrical panel is easier to wire and more effective (can't forget individual machines) and probably cheaper than a bunch of smaller disconnect switches. Also, do you want to unlock each machine every time you want to use it? A single "main disconnect" switch that you lock with a combination padlock (so you can't lose the key) would be simple and easy. Put the disconnect switch up high so your young son can't easily reach it. Yeah, he could grab a ladder, but if he's that serious about turning the machines on without your knowledge, you've got other problems to deal with.


I can put two machines per circuit but I would be pretty much limited on future expansion I suppose.

See my comments in my response above.

Rob

[Bill Lewis]

Mine is a home shop, in the basement. I've got two 200 amp panels. I have separate 240V oulet circuits for the Table saw, Dust collector, and welder (in the garage). I also have another 240V circuit for the compressor. The compressor is hardwired with a disconnect box. I have two 125V outlet circuits, and a separate circuit fo the lights.
I have a closet built around the main panels, in your case you could do the same and lock the closet, or do as Rob suggested, and wire in a fused disconnect between the main panels and the shop sub-panel. Disconnet boxes are made with provisions for a lock.

[Chris Fite]

I have a 90 amp subpanel with a 120v circuit for primary lights; 120v circuit for secondary, task lighting; two 120v circuits at 20A feeding duplex outlets paired every 4 feet around the shop so that there are two circuits available at the same location; a 15 amp circuit for the 36 inch exhaust fan; a 220v circuit at 20A with outlets every 8 feet around the shop, dedicated 220v circuit for the combo machine at 30A, dust collector 220v at 20A, future air compressor 220v at 20A. The radiant, hydronic heat uses a small pump on 120v at 0.8A, so it is plugged into one of the 120 v circuits. The 120v wall outlets have GFCI protection.

One thing that I put in on a lark, after reading someone's suggestion, is a motion activated light at the door. It turns on whenever someone walks into the shop. If you come in with your hands full, you still have light. You also have some light while waiting for the high bay lights to warm up.

The keypad for the alarm is by the front door, outside. I put an awning over the front door, so that it could stand open without falling rain splashing into the shop.

The shop is a separate building that stays locked unless I am using it. This keeps visitors and children out of it. It has its own alarm system, too.

[Tom Jones III]

One thing I have not seen addressed is how do you decide the max capacity of the sub-panel?

[Julio Navarro]

Thanks Rob, all good points

[Rob Russell]

I have a closet built around the main panels ...

If you decide to build a closet around your panel, be sure that the space is large enough and meets the NEC minimums. Remember also that this is a required "working space", so the closet (or space in front of any panelboard) needs to be kept clear.


One thing I have not seen addressed is how do you decide the max capacity of the sub-panel?

If, by "max capacity" of a panelboard, you mean the maximum number of amps that can be distributed by the panelboard, that's part of the manufacturer's label and specifications. In terms of the circuit breakers you put in the panelboard, those can add up to more than the rated capacity. The breaker that feeds the subpanel can't be more than the panelboard's rated capacity.

As an example, let's say you were installing a 100 amp subpanel and put in a 40-slot panelboard rated at 125 amps, fed by a 100 amp breaker in your main panelboard. Assume the 40 slots have (5) 15-amp/240v breakers, (5) 20-amp/240v breakers and (10) 20-amp 120v breakers evenly balanced across the 2 hot legs. If you were running ALL of those circuits at 50% of rated load, you'd be attempting to draw 137.5 amps and the 100 amp breaker feeding the subpanel would trip.

The reality of the amperage draw in a really serious home workshop is that you might draw a simultaneous max of:

25 amps @ 240v for a 5 HP tablesaw
25 amps @ 240v for a 5 HP dust collector
25 amps @ 240v for a 5 HP compressor that happened to cycle on
20 amps @ 120v in lighting to make your shop as bright as day (running at 80% amperage, that's 4 dozen 4' flourescent tubes)
20 amps @ 120v for your kick-butt shop stereo to make you as deaf as a post


All of the above is only 95 amps of current draw and wouldn't trip your 100 amp breaker.

[Tom Jones III]

My question is how do you decide if you need a 100 amp subpanel or a 150 amp subpanel or 60 amp subpanel? Is it as simple as adding up the watts from every thing you can imagine running and making certain you've got a few amps above that? Maybe calculating your max expected load then multiplying by 2?

I've got the panel for the house in my detached garage, so when I wired my garage to be my workshop, I simply used the empty slots in the panel. Now I'm thinking about making a dedicated sub-panel for the shop and placing it next to the main panel so that I can have more circuits.

[Rob Russell]

My question is how do you decide if you need a 100 amp subpanel or a 150 amp subpanel or 60 amp subpanel? Is it as simple as adding up the watts from every thing you can imagine running and making certain you've got a few amps above that?

For a subpanel to feed a workshop, that's pretty much it. For a house, there are a lot of additional rules, but the minimum service requirements still don't come up to be all that large. So, add up your possible concurrent loads and give yourself some headroom. Assume that you don't want to load things up past 80%. There is an NEC rule that says continuous use loads are supposed to draw no more than 80% of a circuit's capacity. Continuous is defined as 3 hours or more, but there is really little in our residential shops that would approach that. So, using the 80% rule is just a nice conservative way of loading your circuits.

Since you're putting the subpanel next to your main service panel, you're not going to spend huge amounts of money on conductors. That's a little different than the subpanels I ran for our addition which were 80 feet or so from our main panel. Anyway, the smallest panel I'd put in is a 100 amp panel with 20 slots. That allows for (4) 240v machinery circuits and (4) 120v general purpose receptacle circuits and leaves 8 slots open for expansion. Run any additional lighting out of your main service panel.

Even if you only think you'll run 40-50 amps worth of stuff at a time, the relative cost of putting in the larger subpanel just isn't that great and gives you flexibility in the future. If you add up your loads and find that you could be regularly drawing close to 100 amps, I'd go with a larger panel. If that turns out to be the case, there's a chance you'll have to go to an electrical supply house to get the breaker. The local HD near us doesn't carry individual breakers larger than 100 amps.

That's my story and I'm sticking to it!:D

[Bill Lewis]

If you decide to build a closet around your panel, be sure that the space is large enough and meets the NEC minimums. Remember also that this is a required "working space", so the closet (or space in front of any panelboard) needs to be kept clear.
Well, I did keep 36" clear in front of the panels, in part becasue I know that that is was the minimum space required, but it also served to box in the water main shutoff as well.
OTOH, I have seen "closets" that are nothing more than a door on the wall that has the panels directly behind it. My neighbors house is this way. This makes sense regarding the code, because once the door is open, you immediately meet the clearance requirement.

[Kent Fitzgerald]

According to the product manual, that HF motor is 230 V, single phase.