Home Electrical Renovation. Adding Power Sources And General Electricity Questions.

Factual Questions
1

Here’s the deal. I’m renovating my house. I basically have to rebuild the interior of the house. This gives me unlimited freedom in designing the house the way I want it to be. I have many custom ideas in my head. So far they have worked out.

My latest project is a particular room where I am going to stash all of my high tech gear and gadgetry. I want to set this room up in a seriously professional way. Aesthetics count. The room is on the second floor, and currently has two seriously outdated outlets. They are two prong.

This room is going to use a lot of electricity. At the beginning, I’m going to have two computers, networking hardware, a stereo system, and a CB, with more added on in the future.

Since I have to rebuild the walls, I’m installing the new cables and wires as I go. I am currently at a block where I have to plan the rest of my design out before I go any further. Here is my idea and what I want to accomplish.

[ul]
[li]Install a new sub breaker box in this room, that feeds off of the breaker box that is in my basement. The current breaker box in the basement is brand new and rated at 200 amps. The new sub breaker box will be at most 100 amps. What kind of cables and/or new breakers do I need to supply the power from the original breaker box to the sub breaker box? [/li][li]Install GFCI outlets along the walls in the room to plug the components into. For aesthetic reasons, I want as few cables on the floor as possible, and no surge protectors to trip over. Will this accomplish the same goal?[/li][li]Each single ganged GFCI outlet will be hooked into its own breaker in the sub breaker box. Is this overkill?[/li][li]The current wiring is two contact copper wire, with no ground. Will the electricity that is travelling this wire between the two breaker boxes be too much?[/li][li]The current wiring and outlets has no ground. What is the easiest way to ground this entire room?[/li][/ul]
Your suggestions are highly appreciated.

2

Some thoughts:

For reasons like insurance, resale value, etc. you’ll want your work to be “to code.” For this you should have some sort of reference book. Nothing hard about it, but it helps to have an authoritative guide.

The correct gauge of wire depends on the current it will carry. 100 amps requires more than ordinary wire. The book will tell you what you need.

The scheme for a “sub breaker box” is a bit heterdox. Have you given thought to how much power you’ll actually be using?

GFCI outlets are not the same as surge protectors.

One outlet per breaker is also unusual. Do you really plan to draw 20 amps or so with one device?

It would be very strange indeed (and probably against code) to put in the sort of mega-service you are describing while using existing ungrounded 2-wire service. You should certainly plan to upgrade this wiring.

3

Some thoughts:

For reasons like insurance, resale value, etc. you’ll want your work to be “to code.” For this you should have some sort of reference book. Nothing hard about it, but it helps to have an authoritative guide.

The correct gauge of wire depends on the current it will carry. 100 amps requires more than ordinary wire. The book will tell you what you need.

The scheme for a “sub breaker box” is a bit heterdox. Have you given thought to how much power you’ll actually be using?

GFCI outlets are not the same as surge protectors.

One outlet per breaker is also unusual. Do you really plan to draw 20 amps or so with one device?

It would be very strange indeed (and probably against code) to put in the sort of mega-service you are describing while using existing ungrounded 2-wire service. You should certainly plan to upgrade this wiring.

4

Sorry about the double post – unbelievable posting delays tonight.

5

First off IANAE (I am not an electrician), however I do have a decent amount of home repair/rewireing experience. That being said I will offer no breaker box advice except that the second breaker box might not be necessary if the existing box has a few unused slots to accommodate more breakers. If you do add a second box you do not need to put it on the second floor unless you want to, and as per your subsequent question the standard gauge household wire will not be sufficient to connect the two breaker boxes. I will refer the question of what the proper gauge for that application up to a better authority than myself.

As to the GFCI questions, I may be wrong and if I am I will cheerfully stand corrected, but I don’t think a GFCI outlet is a safe replacement for a surge protector for say a computer. There are any number of ways to keep a surge bar out of site and not under foot. I do believe your idea of each GFCI line having it’s own circuit breaker is defiantly over kill, unless you are running equipment that draws a lot of power on each line. I believe code around here lets you string up to six regular outlets off a GFCI device so that each of those outlets is protected. If you are uncertain how to wire them that way consult the documentation that came with your GFCI outlet or perhaps an electrician.

Grounds, the best way to get a good ground in the pre-PVC days was the copper cold water pipe. You say you have open walls and speaking as someone who has had to snake wire through tiny drilled holes I must say I envy you, I recommend you make sure that your breaker boxes are properly grounded and then run the standard three wire ROMEX from the box to as many places as you care. Remember, once you seal the walls to make that house a home you wont have this chance again. If you chose not to do this do a continuity test between the nearest cold water pipe (assuming it’s not plastic) and the street side of your water meter, if there is a connection you can get a grounding clamp at any decent hardware store and ground from there.

The opportunity afforded by the necessity of rebuilding most of the interior walls is a great one. Besides updating the wiring and plumbing would consider running an empty two inch pipe straight up the inside of the walls from the basement and up consecutive floors in a few places in case any time in the future you wanted to run some new wire/cables easily, after all ten years ago who would have thought that cat3 or network cables would be something someone would want to string though their walls?

6

All major renovation and new construction must be done to current code. If you are not conversant with the latest code adopted by your city, you should hire an electrician. What you are planning to do is a fairly major (though not particularly complicated) renovation. You don’t want it to be wrong.

In the event of a fire, your insurance company is going to want to know if you had a permit for the renovation and had it inspected by the city inspectors. You really want to be able to answer “yes”.

FYI: GFCI outlets or breakers for this application are completely unnecessary. Ground fault protection protects you, not the equipment. Unless you plan to operate this equipment while sitting in your hot tub, you don’t need the protection.

Also, code will require you to get rid of the 2-wire cabling in the walls. You will have to install grounded outlets and a grounding conductor (the 12-3 romex mentioned above).

Installing a sub-panel off the main: If you are going to connect to the main lugs of the main panel, you will need to have the utility company shut off power to the house while you are doing this connection.

I would highly recommend hiring someone for the panel work, if not the rest.

7

I recommend that you hire an electrician to do this job and that you ignore the advice you have been given here. Some of it is incorrect and could kill.

The correct gauge also depends on the distance the subpanel will be from the main panel, whether the wire is in conduit or not, and other factors. You must get this right or you can burn the house down.

It is against code to ground to an available cold water pipe. If you do this you risk electrocuting someone in the shower. Anyway, your subpanel will be grounded because your main panel is grounded, so this advice was unnecessary.

A subpanel is not connected to the main lugs; it is connected to a breaker of the appropriate size in the main panel. You do not need to have the poco turn off the power to do this.
I point these things out not to embarrass the posters, but to show you that the advice you are getting is dangerous.

8

Good info everyone. Back to the drawing board.

9

GFCIs, by the way, are for wet-area usage. They’re there so you don’t get killed when you drop your hairdryer in the tub.

Why had you planned to put them in, originally–for switch-off capability, or for power-surge protection for your gear?

If you’re getting really nuts, you could probably get a professional power conditioner/surge suppressor. My EE friends speak fondly of Tripp Lite products ( http://www.tripplite.com ).

10

GFCI’s can also be used to convert two-prong (i.e. groundless) outlets to new, three-prong outlets. (Our old house had 2-prong outlets everywhere. I don’t like two-prong outlets. And I didn’t wat to run ground wires to each outlet box. So I installed a handful of GFCI’s and was able to replace all the old outlets w/ 3-prong outlets.) But there are some disadvantages to doing this. I can list them if you like.

11

You should have listed them, because your statement may mislead readers into thinking that they will have a ground if they replace ungrounded outlets with GFCI outlets. Code requires that ungrounded GFCIs be labeled “No equipment ground”. As was stated by another poster, the GFCI outlet protects people, not property. Using equipment which requires a proper ground with an ungrounded GFCI can have adverse consequences. Most equipment is double insulated to avoid these problems (and thus does not have a grounding pin), but equipment which is not (like most computers) can be damaged.

12

I think you are overestimating the load somewhat.

From what I see, there looks to be only one kilowatt at most, but you guys use differant voltages to us, 110V?, which would make the current less than 20 amps.

A 100 amp breaker is way overkill, I just cannot see you using more than 50 amps,most likely around 10 to 20 amps and that would be unusually heavy usage too.

This could easily be run from the main board at a far reduced cost.

The only justification for installing a sub board would be if there were some overriding need to keep the number of appliances affected by an electrical failure down to a minimum by splitting them down to a number of fused circuits.

There is one other possibility, sometines using GFCI outlets is not appropriate in some applications, for example in arc welding, and you would want to keep a few outlets reserved for those purposes so you split your supply between GFCI circuits and non-GFCI.

I am assuming that what you call GFCI devices are what we call RCD(residual current devices) and these are desgned to trip whenever there is an earth leakage current greater than 25mA.
Such devices will protect humans from shock, being very sensitive and fast acting, whereas fuses are only really effective at protecting wiring and property, and are not anything like as useful at disconnecting humans inadvetrantly connected to live conductors.

It is that very sensitivity that makes GFCI unsuitable for certain applications, such as in situations of large capacitance or induction.

DO NOT GROUND TO WATER OR GAS PIPES. repeat DO NOT GROUND TO WATER OR GAS PIPES.
They may be metal above ground, but nowadays most have been replaced by reinforced PVC and are not suitable earthing points.

Earthing is a whole subject on its own, it is quite possible that if you use Romex, and the cable run is fairly long and especially if it passes through interwall Rockwool insulation that you find it is the size of the earth wire inside the Romex that decides the gauge of cable to be used, rather than the current carrying wires.

I would imagine that something like 6mm wire would easily be capable supplying the kind of load you describe, it really depends upon the length of the run and the way it is installed, especially if it is near to things like heating flues and the like.

13

My advice is to listen to StinkPop’s advice. If you want to do this project professionally, hire a professional. Staying alive is more important than aethetics.

14

Most localities allow home owners to do their own wiring. The power company may require an inspection prior to hooking up a new drop that matches your service meter and entrance box

Check for local codes. The National Electric Code is the minimum.

All wiring should be replaced with #12 w/Ground and all receptacles
with commercia gradel NEMA units.

The entrance service also requires a driven ground rod in most localities.

DON’T GO ON THE CHEAP!
If you can’t do it right don’t do it at all.
Whatever the cost of professional help it is cheaper that an electrical catastrophe, fire, loss of life, or other disaster!

15

I am not an electrician, but I’ve just been through a renovation, and did a lot of electrical work (and had a licensed electrician on the job, who did other things, and checked my work).

First, figure out your power requirements. Look on the back of the equjipment, it should tell you the power draw, hopefully in amps at 110/120 volts. If not, you have to do the math: watts = amps * volts. A computer is usually 1 or 2 amps. Networking hardware (i.e. consumer-grade router/switch/etc) is about 0.1 amps each. A complete home stereo setup will be in the range of 2 to 5 amps. You’ve got about 10A, and I’m being generous. You can run a 20A circuit with 12 gauge. If you want “headroom”, install two 20A circuits.

No need. One or two 20A circuits, on 12/2 romex (per circuit) will suffice.

If you have a lot of other rooms you want to hook up, and you want to avoid pulling a dozen circuits up from the basement, then you might want to consider pulling just one feed from the basement (or outside, at the service entrance) to a new panel upstairs. However, 12/2 romex is cheap, a new panel and heavy gauge wire are not. I’d only do this if wiring space was at a premium…

Is this going to be a computer/CB/stereo bathroom? If not, you’re wating your money. GFCI protects you, if you accidentally drop your CB into the bathtub.

You still need surge protectors (or UPS). You can hide them quite nicely, for instance most can be screw-mounted under cabinets, etc.

Unless you know you are going to place a 20A load on each outlet, this is overkill.

Toss the old wiring. 12/2 romex is cheap, about $0.10 per foot. It’s not worth the time, aggravation, or compromised safety to cobble together something with old wire.

Assuming your new panel is grounded, and you run 12/2 romex up to the room, and diligently hook up the ground wires everywhere, all outlets will be grounded.

If you are considering network/audio/video/etc wiring, the time to do it is now. I’d put 2-gang low-voltage boxes (the ones with no back, generally orange in color) all around, and run conduit (1 1/4" rigid PVC, or multiple 3/4" PVC flex if space is tight, strung with pull cord) to each. Run 4" PVC conduit between floors, too. This will let you setup whatever you want, and change it whenever the technology (or your needs) change.

You can put speaker wire, phone, networking (cat5e/6 or fiber), video (RG6 quad), or whatever you use to get signal from your CB antenna on the roof (RG6 quad?). If you use decora inserts (like this http://www.lashen.com/vendors/Leviton/Datacom/decora_quickport.asp) you can use regular decora wallplates, and install whatever you want (here’s a bunch: http://www.lashen.com/vendors/Leviton/Datacom/AssortedInserts.asp, http://www.lashen.com/vendors/Leviton/Datacom/Cat3_5Jacks.asp). You don’t have to buy Leviton connectors, anything that is keystone form factor will fit.

16

I’m not misleading, I just didn’t want to get into too much detail. Yes, the outlets have to be labeled. And yes, a real ground would not be present. But the NEC does allow you to do this, for better or for worse.

In this thread we came up with a bunch of reasons for having a ground. It can be stated that a properly-working GFCI will suffice from a safety point of view when no ground is present, but some equipment requires a ground for other reasons.

17

Following up on myself here…

Most of the clutter with computer/stereo/tv/etc is not with the power cables, it’s with all the other cables hooking everything together. If you can bury all of this stuff in the walls, and make them pop up at convenient locations, the overall look is much cleaner.

For instance, if you want to mount rear speakers up high, you can run speaker wires from the receiver into a box in the wall, then have them pop out a few inches from the speaker mounts. Or you can install the speakers right in the wall, using either speakers designed for this purpose (note: there is a lot of cheap crap out there!) or quality car-audio stuff. All you will see is the grill.

For ideas, try www.smarthome.com or www.futurehomesystems.com. There are a lot of other suppliers out there - many at lower cost, too.

18

You characterize my advice as capable of killing, then effectively admit it is correct, though incomplete. You omit the subsequent line of my post, in which I suggested use of a suitable reference book.

All in all, yours was not a fair post.

19

Two cents here on the number of circuits - I’d run four.

Put the computers on one circuit.

Put the audio gear on another, on the other “side” of the bus - this will help keep any garbage that manages to get out of the computers from getting into the audio.

Consider a circuit just for the audio amplifiers - if you’ve got say 100 watts of power per channel and a subwoofer, you’re sucking down at peak levels 600 watts of electricity, and possibly more.

Another circuit for the CB, desk lamps, etc.

Consider running “dead” Romex to wherever the equipment will live in case you get a new toy that devours power. Just run it to a box with a blank cover, and don’t connect it to anything. Label its other end (also ending in a box with a blank cover near the breaker panel) as “spare circuit in southeast corner” or whatever’s appropriate. A little extra Romex in the walls is cheap and will save the aggravation of trying to fish it later on.

Likewise, a receptacle in the ceiling and adjacent to it, a low-voltage box with PVC conduit (as described by 5cents) running to the equipment area in an appropriate spot if you ever think you’ll have a video projector.

Everything’s 15-amp receptacles with 12 gage wire. I’ve always been uncomfortable with running wire right at the limits of its capacity.

20

Not so,

If you are getting signal noise components going from computers into audio equipment through the mains wiring, this method will not separate them.
Both circuits will be supplied from the same source and the noise will just route itself around, and this is why you neighbors central heating controllers can cause interferance right the way down a whole street.

The only practical way domestic users can keep mains noise down is by using conditioning sockets, filter units to the errant equipment.