Full Main panel

[rjwaldren]

I have only one full space left in my main panel. I haven't finished ID'ing the last few circuits yet - but they've done a nice job using up and loading up all of the circuits. For example, the 15A circuit that feeds my garage outlets/lights is the same circuit that feeds the wall outlets/light in the Laundry room, 4th Bedroom and closet. This continues throughout the entire house with multiple rooms fed by single breakers. The panel is already full of tandem breakers.

I have a couple of options - Each with their own questions. Either add a sub-panel or reconfig the main panel. If I add a sub panel I'll still need to free up another space in the main to accommodate a 240 circuit. Here's main question - I currently have a 20/40/40/20 common trip that is only feeding the dryer. The outer 20A legs are not in use. Can I remove the trip bar from the outers and use them as individual breakers? Or can I upgrade the breaker and use the outer legs to feed a sub panel?

Ultimately I want to seperate the garage from the rest the house - leaving the inside on the 15A circuit and adding at least one 20A circuit for garage outlets and another for the lights.

[master53yoda]

The dryer breaker assembly you just mentioned throws a flag at me. most dryers should be on a 30 amp #10 circuit. also the two 20s with the dryer if combined would provide a 20 amp 240 VAC circuit or two 20 amp 110 vac circuits.

You did not mention how big the panel is or how big the house is. Is the panel a main breaker panel or does it have six mains with a lighting subsection in the panel.

Typical circuits would cover 600 sq ft of bedroom spacing on each 15 amp circuit. or 800 on a 20 amp circuit. most living rooms and front rooms would each receive one circuit. the kitchen would have 2ea 20 amp GFI circuits with a separate circuit for the dishwasher if installed The washing machine and furnace should be on dedicated circuits. the bathrooms could be included in the bedroom square footage.

I worked on a house once where the homeowner had wired it and run every plug back to the panel 1200 SQ ft house with a full 200 amp main breaker panel .

[jAngiel]

I'm not an electrician so my terminology is not correct but at my house they came in with another subpanel from outside. The put in some kind of breakout box and ran another main to a subpanel inside. The most expensive part was this huge wire that ran from the breakout box to the subpanel, it was something like $30 a foot.

[ragswl4]

I'm not an electrician so my terminology is not correct but at my house they came in with another subpanel from outside. The put in some kind of breakout box and ran another main to a subpanel inside. The most expensive part was this huge wire that ran from the breakout box to the subpanel, it was something like $30 a foot.

That must have been one humongus wire. I am buying 2/0 wire (200 amp) for $1.53 per foot.

[rjwaldren]

Art,
The dryer circuit is okay, it was recently part of a correction where my HVAC breaker was under sized by the builder. The wire is sized for 40A, but I have seen recommendations to limit dryer circuits to 30A, would you advise doing so?

Whats installed in that position right now is a 20/40/40/20 quad so the inner and outer 2 breakers are tied together with a clip. Are you saying it may be legal to remove the clip from the outer 20A's and use them as individual 20A circuits?

BTW...This is a 125A main panel with 14 full size positions, standard for the area. The house is just under 2000sq. The GFI's and Kitchen/laundry circuits are as you would expect - Individual dryer, stove, microwave, dishwasher, etc. The electrician that did the HVAC work said there would be no problem adding a 50 to 80A sub-panel to the current setup.

[Crash2510]

I'm not an electrician so my terminology is not correct but at my house they came in with another subpanel from outside. The put in some kind of breakout box and ran another main to a subpanel inside. The most expensive part was this huge wire that ran from the breakout box to the subpanel, it was something like $30 a foot.

go to your electricians house and steal his car because you own it. You must have a 800 amp 3 phase panel for the wire to cost 30 a foot and i am not kidding.

Sounds like you may have a federal pacific panel. If i were you I would check the panel really really well for any corrosion or burning (not a great product) before deciding to add a subpanel. If everything is ok I would pull out a couple of the old breakers to free up space and put them in a new 60 amp lug only panel. If I were you I would also change the dryer to a regular double pole 30 amp breaker for the protection of your dryer. Using a 40 amp breaker on 30 amp wire can be very dangerous if your dryer malfunctions.

[rjwaldren]

That's what I'm starting to think. Pull a sub into the garage (opposite side of the same wall as the main) and move the lights/outlets to the new panel, leaving everything else on the main. Shouldn't be more than 3 feet of wire to connect to the main. How large of a sub-panel can I get away with adding with typical residential 125A service load? Upgrading to 200A is not an option.

The main is a Siemens panel about 6 years old. 12/24 with a factory 125/125 service disconnect breaker.

[master53yoda]

Art,
The dryer circuit is okay, it was recently part of a correction where my HVAC breaker was under sized by the builder. The wire is sized for 40A, but I have seen recommendations to limit dryer circuits to 30A, would you advise doing so?

Whats installed in that position right now is a 20/40/40/20 quad so the inner and outer 2 breakers are tied together with a clip. Are you saying it may be legal to remove the clip from the outer 20A's and use them as individual 20A circuits?

BTW...This is a 125A main panel with 14 full size positions, standard for the area. The house is just under 2000sq. The GFI's and Kitchen/laundry circuits are as you would expect - Individual dryer, stove, microwave, dishwasher, etc. The electrician that did the HVAC work said there would be no problem adding a 50 to 80A sub-panel to the current setup.

1. If the wire on the drier circuit is #8 it is OK on 40 amp If it is # 10 change it back to a 30 amp breaker.

2. Yes, if you remove the tie bar the two 20 amp breakers become just 20 amp 110 VAC breakers and can be wired to two 20 amp circuits.

3. 125 amp for a 2000 sq ft house with AC and electric kitchen stove is a full load for 125 amp panel and service entrance. Adding another panel is do-able but the meter base and the inlet wires are already at load. If you want to add more then the another 2 or 3 20 amp circuits you really need to look at a 200 amp service. I no that isn't what you wanted to hear but it is reality. the electrician is probably a little out of line saying you could add a 80 amp subpanel to your application. He isn't thinking about the fact the the meter base and incoming service wires are already loaded.

4. this is an estimated load calc
3 ton AC 30 AMPS
stove with oven running 35
clothes dryer 22
lighting and misc. 15
subtotal very possible load 107 amps there isn't much left and the above load is not out of line

My home is similar in size and with the 2 hp pool pump running I have measured 120 amps on my home in the summer at dinner time.

[Crash2510]

Art,
The dryer circuit is okay, it was recently part of a correction where my HVAC breaker was under sized by the builder. The wire is sized for 40A, but I have seen recommendations to limit dryer circuits to 30A, would you advise doing so?

Whats installed in that position right now is a 20/40/40/20 quad so the inner and outer 2 breakers are tied together with a clip. Are you saying it may be legal to remove the clip from the outer 20A's and use them as individual 20A circuits?

BTW...This is a 125A main panel with 14 full size positions, standard for the area. The house is just under 2000sq. The GFI's and Kitchen/laundry circuits are as you would expect - Individual dryer, stove, microwave, dishwasher, etc. The electrician that did the HVAC work said there would be no problem adding a 50 to 80A sub-panel to the current setup.

I was wondering if the square footage was all living area or if it included a basement garage etc. Even at that we have to remember that probably a good chunk of this sq footage is bedrooms which have very small total loads.

I know what yoda said about your amp load but you should be fine adding a subpanel to get the junk out of your old panel. You have to diversify the load a little when calculating for a house because if you used the worst case scenario everyones main breaker would be tripping left and right. Only on rare occasions would an average household go above 100 amps on peak demand. A 60 amp lug only subpanel with 6-3 romex as the feeders should suit your needs fine. just don't think you have to put everything into the new panel.

hope that helps

[crokett]

If it matters, I have a panel outside with breakers for HVAC, dryer, dishwasher, basement sub panel and water heater. The breaker that feeds the basement sub is 90A, so basically most of my house is being fed by 90A. I do not have a main breaker shut off to disconnect me from the grid. This is why I have transfer switch. Yes, I know if I shut off the breaker outside that feeds the sub I've done the same thing. I asked an electrician about this a bit ago and he said when the house was built, no main shutoff was allowable. Since the rest of the house was built on the cheap, I am not surprised they did not put one in.

[rjwaldren]

Well, if I can get away with using the outer breakers on the quad I can get all of the circuits I presently need from the existing panel. That would be moving the garage off of the 15A that it is currently ganged to, installing two new circuits for garage outlets and one more for garage/attic lighting. That will leave 1/2 breaker slot empty if I use tandems.

Not ideal but money is tight and still doesn't solve the problem of a 240 circuit to the garage. I don't have that problem yet, but would like to in the future.

One more question regarding sub panels. I would mount a sub nearly back to back (inside vs outside) to the main/meter panel. I've seen conflicting advice elsewhere about the need for a disconnect breaker in the sub. Some say mandatory (if not side by side), others say only the main panel end and optional on the sub.

[Crash2510]

disconnect in the sub panel ie main breaker is not required by code

go with the lug only panel its cheaper (if you decide to do it)

[master53yoda]

If you install a subpanel There MUST be a breaker for the subpanel between the meter and the subpanel. If you feed it out of the main panel the breaker in the main panel is the main for the sub panel. If you feed it out of the meter base it must be a main breaker panel. Code will allow six main breaker panels feed directly from the meter base but this would probably never be seen in a residental application. The meter base in this instance is only rated at 125 amps at 80% continous load, 3 hours duration, this reduces the avalable load to 100Amps.

You are correct in saying that you can use the other two 20 amp circuits in the garage. Leave the lighting on the 15 amp circuit and run new #12 wire attached to the 20 amp circuits, DO NOT connect the old 15 amp circuit wire to the 20 amp breakers.

If you looked at the load example I gave, I diversified the lighting etc. load as only 15 amps. those other loads that I listed are assuming gas water heater and furnace. If you have a gas dryer or range it would substantually reduce the electrical load.

The code does not allow diversification of range, dryer, and AC in the calculation of service sizing. If you overload the Meter base and incoming service and cause a fire your insurance could tell you tough luck. As brought up in another thread the code is provided by the fire protection industry and is a loophole the insurance companies look at.

[Crash2510]

I'm sorry I must have misread. Are you talking about feeding the sub panel out of the meter base or the main panel if its the main panel the sub doesn't need a breaker.

Yoda code does allow for diversification of the range you can see this in the old 2002 code book article 220.19 and in the 2008 code as 220.55. THe first range is 80% second 65% and so on for most normal ranges. Dryers are calculated at 5000 watts or the nameplete rating usually not more than 25 amps.

[master53yoda]

this is an estimated load calc
3 ton AC 30 AMPS
stove with oven running 35
clothes dryer 22
lighting and misc. 15
subtotal very possible load 107 amps there isn't much left and the above load is not out of line

The estimated loads did de-rate the range to 80% and close to real dryer loads, the load on the house is still close to max for a 125 service. What I am saying is that if you choose to put a 60 amp sub-panel in the shop and use it with high HP saws and fans etc. you are pushing the service in the summer. Also I only used the AC at 3 tons. If the AC is larger then the Load goes up. I will always provide conservative but safe information when I comment and make sure it is not misunderstood. Such as specifiying the difference between a panel fed from the meter and one fed from the main panel. When we work in the field of electrical there is so much that we assume but others that are not in the field don't no the basic assumtions we are working under.

I have seen melt downs on improperly sized equipment many times over the years.