dimming lights

[burnjob]

ok ... here's another one
i have a panel that is equipped with a "100 amp" main breaker
the dryer is on its own 30 amp breaker (of course) ... yet everytime that the dryer starts up ... other lights in the house dim ... i don't think that this is normal and i wonder if it has to do with what wgoodrich mentioned in his fourth post at

http://www.selfhelpforums.com/viewtopic.php?t=136

when speaking about my phantom voltage situation and he mentioned about "back feed" ... or perhaps there is another reason ???
the dryer is only a year old (bought new) and although i have not tested it to determine if it is drawing the correct power or not ... i assume it is - i know, don't assume ! - as it is new and i would also assume that they are tested before leaving a manufacturing plant or wherever they're made
thanks

[Wgoodrich]

This I believe to be a different story than the back feed discussed in the post you mentioned.

I don't have enough information to make a solid hit on what you have yet but suspect I am very close.

I need to know if the dryer is in a main service rated panel of a nonservice rated panel [aka sub panel] Also does any of the lights that dim also shut off if you turn the 30 amp breaker off of the dryer? This would lead us to believe where the culprit is.

I am suspecting that either you service is too small or close to being minimum in size or you have a voltage drop problem starving electricity.

Answer the above questions and in the meantime try performing a demand load calculation to discover what your minimum service size is supposed to be per the NEC rules. This will tell us whether to look elsewhere.

http://www.homewiringandmore.com/homewiringusa/2002/definitions/demandcalc02/DwlingDmdCalc02.html

Curious

Wg

[burnjob]

the panel is the main panel for the house and there are no sub-panels ... it is a modular home (built in a factory and erected onsite) and is 25 years old. the main panel is on the main floor and has one 100 amp main breaker at the top.
when i turn off the dryer breaker there is no effect to any other lights or receptacles ... no other lights go off and all the receptacles still work.
could it have anything to do with a faulty breaker for the dryer ?
could it be what you hinted at earlier about the main breaker being underrated for what is actually being drawn ?
thank you

[Wgoodrich]

JUst out of curiosity does you home have steel I-beams under the floor of your home. Your home came in two sections to your lot if I am picturing the home you have right. Does your home have 4 steel I-beams under the floor of your home with peirs supporting those I-beams, or do you have all wood under the floor of your home with a piers supporting a wood beam? Just curious.

You opened up more things it could be causing your problem instead of centered down on the cause.

You home most likely came in two sections. This means you have branch circuit junction boxes that join the two halves together. These junctions joining the two halves together can be a prime suspct that may have a loose wire nut in those junctions causing that set of lights to dim.

Also in a modular of manufactured home your panel is remote inside your home with a main disconnect outside your home.

Now we need to know if all the lights that dim are on the same branch circuit or on different branch circuits. If on the same branch circuit then we most likely have a loose connection either in the panel or in the branch circuit itself.

Next you said 25 years old. This leads us to suspect you have back stab receptacles that is also a prime suspect causing the dimming of lights.

If these dimming lights are on different branch circuits then we have centered down on the area between the point of connection of the utility company to the inside of your panel in your home including your main disconnect outside if you have one.

Tell us how close I hit on the design of your home and if you have an outside main disconnect and also how far inside the home the panel is located. Then tell us if those dimming lights are on more than one branch circuit or on one certain branch circuit. Be sure of that answer or we will go on a wild goose chase.

Curious

Wg

[Anonymous]

My home does not have any steel beams - it is all wood construction.
Yes, my house was put up in two separate sections. It does not have a separate disconnect or panel on the outside of the house. I live in BC, Canada and i assume that this difference is due to different rules and regulations for the different countries (USA & Canada) and given that the house was built 25 years ago there could even be differences in the local, provincial or federal rules and regulations and if it is now code that a manufactured home is 'now' to wired with a separate shut off - it may not of been that way 25 years ago.
I don't know if there are any junction boxes for the purpose of joining the wiring of the two halves of the house ... that's assuming that the house was wired in the factory and not onsite.
this is what is there for breakers:

Main..........100 amp

15.................................15
40 range.......................15
40 range.......................15
15.................................30 dryer
15.................................30 dryer
15.................................15
15.................................15
15.................................15
15 water htr.................15
15 water htr.................15
15..................................15
15..................................15

now that i look at the list of breakers in front of me on the screen ... it appears to me that perhaps there are too many breakers for the 100 amp service main breaker ... what do you think ?
thank you

[Wgoodrich]

If you home is with gas heat and not central a/c with an electric oven or electric range and electric water heater you house 100 amp main service is maxed out if not inadequate if your home is say 2500 square feet.

You show no 20 amp branch circuits but all 15 amp branch circuits. If all you have is 14 awg wiring, with a main panel that is maxed out this alone would explain the dimming of lights when you dryer is started. You 14 awg is barely enough to deliver full power to your lights if your service was adequate. If you service entrance conductors serving you entire house and you main service rated panel is also minimum the inrush of electricity used when the dryer is in start mode coming to full speed you should expect your lights to be starved of electricity. Then if your power company also shorted their wire size that would agrivate your dimming of lights.

Even back in the time your house was connected the NEC [unknown as of now the CEC] required the main disconect to be installed either outside all structures or nearest point of entrance inside your home. Problem is your local Inspector rules how far nearest point of entrance is allowed into a building.

Take a voltage tester and measure from one hot on the line side of your panel's main breaker to the neutral bar of your panel. Start your dryer and see if the voltage reading drops. Suspect you will find it does drop in voltage during the start phase when your dryer starts. Then the voltage will come back up.

Let us know what you find.

Wg

[burnjob]

can you explain what the 20 amp branch circuits are that you mentioned ? what are they for ? why is there a need for them compared to regular 15 amp circuits ?
thank you

[Wgoodrich]

The NEC today requires 20 amp branch circuits to serve designated heave usage areas. Small appliance branch circuits [all receptacles in kitchen, dining, nook, and pantry are small appliance branch circuits] require 20 amp 12 awg branch circuits dedicated to receptacles in the above mentioned areas only not to leave those rooms.

Then bathroom receptacles are also required to be served by a dedicated bathroom receptacles circuit 20 amp 120 volt 12 awg branch circuit dedicated to serve bathroom receptacles only, no other rooms on that bathroom receptalce circuit.

Then laundry room receptacles are also requried to be served by a dedicated laundry receptacle circuit 20 amp 120 volt 12 awg branch circuit dedicated to serve only receptacles within that laundry room no other rooms allowed on that branch circuit.

Now the reason these current rules apply is due to past experience over the years of the far past when 14 awg wire was used combining the kitchen and say a bedroom or a living room on that same 14 awg 120 volt 15 amp branch circuit as wired in the old days we experienced dimming of lights and breakers tripping due to overloaded branch circuits.

Example of the reason for the dimming of lights in the above discribed circuit as an example is that any kitchen appliance that has resistant heat such as friers, electric skillets, coffee pots, electric sandwich makers, toasters and many more small appliances found in the kitchen that are with resistant heat will cause the lights to dim that are on that same 15 amp branch circuit. A small appliance such as discribed above say a toaster of coffee pot normally pull by themselves only one toaster or only one coffee pot will pull approximately 1500 watts. A 14 awg 15 amp branch circuit maximum capacity is 1800 watts. When you turn on that one toaster or one coffee pot that appliance just sucked all the electricity from that 15 amp branch circuit to serve that toaster or coffee pot. When that happens that happy light bulb that was on the same circuit and running fine all day just got robbed of the electrical power it was using by that toaster. This makes the light bulb starve for electricity.

Now you say but this 15 amp circuit is not in one of those rooms mentioned. That dimming can still happen in say that bedroom that is served at the oppossite end of hte house from the main service. That 15 amp branch circuit serving say only that bedroom has a table light running. If you wife plugs in a iron for an ironing board that iron just sucked most of the power from that branch circuit making that light that was running fine dim down starved for electricity because you guessed it that iron pulls also approximately 1500 watts to the capacity of 1800 watts of a 15 amp branch circuit..

You listed all your branch circuits and did not mention one 12 awg 20 amp 120 volt branch circuit. This led me to mention that the dimming is very possible and probable becuase those appliances if not all at least some are used daily in your kitchen, laundry, and bathroom. Oh, forgot to mention that bathroom. Now what could cause lights to dim due to being starved of electricity in a bathroom. Those women have nothing less than us. They love tool time also. That little hair dryer plugged into that bathroom often are rated in watts somewhere around 1500 watts also. Sound familiar. Think maximum capacity of a 15 amp branch circuit max is 1800 watts minus 1500 watts leaves 300 watts left to run all else running on that 15 amp 1800 watt branch circuit. Now while the daughter is drying her hair and you started a pot of coffee and both circuits are on that one 15 amp 120 volt 1800 watt branch circuit then you just loaded a maximum rated 1800 watt branch circuit with 3000 watts. About double the ability for that 15 amp branch circuit's capability and also overcurrent device [breaker or fuse] rating protecting that 15 amp branch circuit. Guess we should about now expect not only the dimming of lights on that 15 amp branch circuit trying to carry 3000 watts of load and only being able to carry 1800 watts of load, but we should expect to have to put our pants on and go to the garage and replace that fuse or reset that breaker after it cools down because we well overloaded that branch cirucit. At least we hope that breaker or fuse will trip or blow before that 14 awg 15 amp rated branch circuit conductor turns red hot and sets the house on fire. This is why many people find their 15 and 20 amp branch circuit fuses to blow in these older wired homes. That is ok though because about 50 % of those people will cure that fuse blowing problem by replacing that 15 or 20 amp fuse with a real strong 30 amp fuse. Now we can run both that hair dryer and coffee pot on that 14 awg wire and we won't be bothered by any fuses blowing at least until that 14 awg wire overheats and we have a new source of heat called a house fire.

The above discription was not meant to be sarcastic it was meant to catch many who will read this post that have indeed replaced their 15 or 20 amp fuses with a 30 amp fuse. Maybe that discription above may prevent one house fire that may have hurt someone just be a person stopping by with curiosity to read what you and I have been discussing.

You should see by now that while older homes may be considered as safe if not in ill repair and still original as it was when it met code at the time of construction we have progressed to loading our houses way past what was expected at the time when they installed 15 amp wiring throughout a home.

I know you are thinking my home is not that old. Remember I mentioned that manufacture and mobile homes have been controlled by much older codes that were outdated the day these manufactured or mobile homes were built meeting that decade or so older NEC rules controlling this alternative building method of mobile homes and manufactured homes.

Remember if the fuses and breakers are sized right the 14 awg wiring in kitchens, bathrooms, laundry are still safe because these branch circuits are protected not to exceed their ampacity rating. Yet dimming of lights in the old wiring styles using all 14 awg wiring in your branch circuits is almost a certainty.

Dont get my statements in the wrong context. Manufactured and mobile homes are purposely controlled by older outdated Code versions in an attempt to enhance the primary goal of these manufactured and mobile homes. Manufactured and mobile homes are an alternative building method using our engineering skills to lower the cost by using our inovative engineering knowledge. While at the same time further reduceing the cost factores by forgiving these alternative building methods allowing the alternate wiring methods as well as plumbing and heating etc. to further lessen the cost factors. The prime goal of manufactured homes and mobile homes were at their conception and still are today intended to lower the cost of these homes built using our engineering knowledge to make an affordable home for those people who want a new home but can't afford those 1/4 million dollar custom built homes. Kind of like trying to give younger people a place they can start till they can afford that expensive built to custom homes.

Now you have a parallel cause that may be causing your dimming of lights. You mentioned you are in Canada. I look at Canada to normally be remote areas. If you live in a remote area and not a big town then you may have a power company that struggles to carry electrical power long distances from their distribution system. This may provide at the start a weak power source to your home. Then if there is a distance of more than say 250 feet going to your home you would have a further voltage drop concern due to a long distance from the serving transformer to your home. Then if you add the smaller 14 awg wires in your home you should see now how dimming of lights may be something that you will have to live with in your conditions. A lot of what i am saying may not apply to you but if you are having dimming of lights then one or more of the above will be the factor causing that dimming of lighting.

My guess at this time is that if the dryer is a 220 volt electric dryer and is truly the electrical load that is causing general lighting to dim then you either have an undersized service entrance conductor from the meter to your house panel or you have a long distance to your transformer causing dimming of lights or you have a weak power source from the utility company having to go a long ways to get you factory power. Or you have a combination of one or even all mentioned in this paragraph.

The reason I am saying this is the only common denominator in this dryer and your general lighting is that service conductors between your meter base and you and the service drop or service lateral between the meter base and your serving transformer. The dryer if electrical and not gas then the above would apply.

If the dryer is gas and if that 120 volt dryer is on that same branch circuit with the lights that are dimming then you should install a new branch circuit to your gas dryer and the dimming should stop.

Hope this helps

Wg