Wiring a general purpose hobby/repair basement lab, any advice?

Thread Starter

DarthVolta

Joined Jan 27, 2015
521
So I'm about to have the basement in the house I rent rewired, and I'm putting my hobby repair lab down there. I barely work on anything high-power, maybe a few hundred watts. If I get adventrous when I learn a bit more, I might try repairing vacuum cleaners and microwave's/ washer's/dryers, household level stuff.

I've been watching stuff like this about how current overloads, from short-circuits, are meant to be as high and as fast as possible, to trip the breaker. And how Earth grounding in any ordinary house/building will never be low impedance enough to trip the breaker, in the event you are in parrallel with an energizezed surface and the Earth or stuff bonded to it like a concrete floor.

Then there's Ground fault protection plugs, which, off the top of my head, use magnetics to compare's the current in a load, to the current directly returning on the neutral line, with the rest returning through bonding to Earth (hopefully not through me) and then back to the panel, back to neutral line then back to transformer to complete the loop. I think they use them a lot in Britain, but they are usually just in bathroom's and now-a-day's kitchen's in Canada. I can't say I see them much in anybody's youtube home lab video's ???

I have a 500 or 1000W isolation transformer, and current limiter/light-bulb, and an auto-transformer of also 1kVA or more. So I'm going to mount that all together, with proper switches/etc, basically like Mr.Carlson EE guy did.
 
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dendad

Joined Feb 20, 2016
3,617
Lots of power points is a good start.
The first power point on each of my work benches has the Earth leakage protection built in, and that loops to all the other points.
And how Earth grounding in any ordinary house/building will never be low impedance enough to trip the breaker, in the event you are in parrallel with an energizezed surface and the Earth or stuff bonded to it like a concrete floor.
This Earth leakage sensing is what you need for that as it is not the current that trips the breaker, but the unbalance between live and neutral. You should not rely on tripping a current overload breaker to protect you from getting zapped as only a few mA are needed to kill you!
Mounting the power points on the bench itself is a good idea when you are renting, then all you need in one power point. No extra wiring for you to do, unless there is no power point there to start with.
The isolation transformer, plus Variac with the lamps as you have above is a worth while addition. Very useful.

A good variable power supply with adjustable current limit is a must. I have a 0-30V, 5A one. Also, fixed supplies of common voltages. One main one I use is 24V, as it is what most of my industrial control designs use. Also, 12V and/or 13.8V.
What test equipment do you have at present?
 
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SamR

Joined Mar 19, 2019
2,789
So far I have 2 12VDC SMPS for my HF XCVRs and AMP, 2 0-30VDC 5A bench PSUs, 7A Isolation transformer & Variac, 120/12VAC center tapped 1.5VA XFMR w/ LM317 regulator homebrew, 2 sig-gens, buckets of wall warts, and a couple of other homebrew PSUs in the works. Plus all my radios, scope, computer/monitor W/ UPS, lamps, audio amps, bench multimeters, soldering station, hot air station, vacuum desoldering station, etc. I have one dedicated 20A service outlet @ the bench plus another 20A shared service outlet for the room. Never enough outlets so I probably have 6-8 multi-outlet power strips in use. It gets warm in here but I do have a ceiling fan that helps.
 

Thread Starter

DarthVolta

Joined Jan 27, 2015
521
OK, and I know having a GFP plug will also not save you if for instance you put a hair-dryer in the sink, and then your hand the water while standing on the floor, that still won't trip the circuit breaker.

I have a proper DC PSU, and a few little SMPS and transformers. I have some computer PSU's I'd like to test, repair/etc someday. 1 is 1,100W. I have 1-4 scopes, 1-3 benchmeters. Signal gen, 80W soldering iron, probably a 1000W hotair station.

Really I better add up the the rated power of this, and add on a 750W computer PSU to the same area.

In theory, the computer could pull near 63% of a 120V*10A=1200W. (not that my CPU/GPU/extra's would ever do so)

What makes for the quiest ground/com bus when wirring this all up over/on/behind a bench ? And what if I'm using 2-3 10A feeders lines ? Overall , the basement is not going to have very much power, so I might not get much that way. Then there's the 240V washer/dryer circuit. If I ever wanted to test some motor or something, it's only to jumper from that 120-240 rails, when I'm not using the washer/dryer.

I need a kill-a-watt meter. I could safely measure the AC current on my Brymen handheld, to the big power bar, feeding my main stuff right now. I suppose I should do that. i could probably do it with my new DMM in ACV/ACI mode, but that sounds too dangerous to consider.
 

SamR

Joined Mar 19, 2019
2,789
10A feeders? Older homes general lighting distributions circa 1930-50s with screw-in fuses were 10A, early residential breakers 15A and for the last 50 years or so most homes have 20A feeders. At least here in the US.
 

MaxHeadRoom

Joined Jul 18, 2013
21,629
I would include a 240v outlet also, especially if repairing household appliances etc.
For the bench 120v outlets, there is the multi outlet strips that mount either on the front or along the rear of the bench.
Max.
 

MrChips

Joined Oct 2, 2009
22,096
I build my own work benches with 2 x 4 and whatever you can use for a counter top, e.g. doors etc.
I put at least one shelf below the bench, at least 10" or 12" off the floor. Then you can put cardboard boxes on the floor or you can build wooden boxes with optional casters on them.

I put a 5ft long power strip on the front horizontal 2x4 under the bench for a woodwork bench, etc.
You want to be able to find outlets easily for power tools.

For an electronics workstation the power strips (or power bars) go at the back on or above the workbench, this way the clutter of electrical power cords go behind the instruments.
You can never have too many power outlets, 8 to 12 at least.

Think about lightning. LED light fixtures are the way to go. Check the colour/temperature before you buy.
2700K is a warm colour. I prefer 5000K daylight.

Some LED fixtures have auto-sensing. That would be annoying when you are sitting stationary and the light goes off. I have those in the garage, for example. For the electronics work area I would go with a wall switch.
 

schmitt trigger

Joined Jul 12, 2010
330
Definitely lots of power outlets and then some more. Believe me, they will all be used.
The circuit breakers should be ideally close by. It is a real bummer to trip a breaker and then have to go up a flight of stairs or outside to restore it.
 

SamR

Joined Mar 19, 2019
2,789
Living in a rented space, I would be planning on building something I could take with me when I moved. Have them add what you want and where, if you can, when the basement is rewired. Then think about plugins that you can dismantle and take with you when you move.
 
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