FAQs on building electrical system installation, troubleshooting & repairs & electrical hazards.

Set #2 of Questions & answers on how to install, inspect, & troubleshoot building electrical systems, appliances, components.

Building Electrical System FAQs-2

These questions & answers about building electrical systems, wiring, & components were posted originally at ELECTRICAL INSPECTION, DIAGNOSIS, REPAIR - home - be sure to see the suggestions at that page.

On 2017-01-22 by (mod) adding GFCI protection

Terry,

GFI protection (ground fault interrupter) adds electrical safety for circuits such as wall receptacles (wall plugs or "outlets") in high risk areas such as in kitchens, bathrooms, and outdoors. There are two ways that protection, also called GFCI, can be provided.

1. a special GFCI circuit breaker (or more than one) installed in the electrical panel will protect everything on that electrical circuit

but you may not have any of those devices in the electrical panel. Instead,

2. a GFCI wall receptacle (wall plug or "outlet") may be installed, for example in a bathroom or kitchen. In that case ground-fault protection (you're touching a live or leaky electrical appliance plugged in to that receptacle and you touch a water pipe, causing a fault that lets electricity flow through to the earth - ie you get shocked) - anyhow, if the receptacle is properly wired and IF it has a GFCI receptacle installed, GFCI protection will be provided for whatever is plugged-in to that receptacle AND it will be provided for any wall receptacles that are wired "downstream" from that receptacle.

In other words if a GFCI is wired into receptacle #1 in a bath and that bathroom circuit then sends power FROM that receptacle on to another receptacle in a bedroom or in another bath, those receptacles are also protected.

You can see GFCI devices to see what they look like here at InspectApedia: see https://inspectapedia.com/electric/GFCI_Inspection_Safety.php and also see https://inspectapedia.com/electric/GFCI_Electrical_Code.php

See your other recent comment and our reply at https://inspectapedia.com/Manufactured_Homes/Mobile-Home-Electrical-System-FAQs.php

On 2017-01-21 by (mod)

Re-posting from an obsolete copy of this web page:

AUTHOR:Terry (no email)

COMMENT:I live inva 14x70 mobile home 1984 should I have a gfi breaker in my panel box if so where?

On 2017-01-19 by CallieMom - blue flames shot out of the breaker box

I live in a single wide mobile home, used. I turned the microwave on to defrost meat, circuit breaker tripped. I went to the breaker box and flipped it back on. I tried using the microwave again and the same thing. I also went back to the breaker box and when I flipped it, blue flames shot out.

Then within 2 minutes my whole home went black.

No breakers were tripped. I flipped the main breaker switch off then back on, the only thing that come back on was my master bedroom, bathroom and front porch light. I had a friend come look at it. He tightened everything and checked voltage. After he left my home went black again with a loud pop,

I started smelling a burning smell in the wall of my kitchen and down my hall.

I woke my children and sent them outside. I flipped the heater breaker off in my hallway, flipped my main breaker in my home off, also the breaker at the meter base off. Come back the next morning, smell is gone, flipped meter at pole on then inside breaker on. All plug ins work, master bathroom has lights, but nothing else will power on. What do I do?

On 2017-01-15 by (mod) can power bumps cause problems with household appliances?

Marylin,

Usually we agree that the simplest explanation is the most-likely one, and I'm not a bit fan of coincidences. So I understand that a power loss can cause several other things to start acting oddly, particulary things connected to the electrical system.

The thermocouple on a gas burner is not, itself an electrical part, though it does control a gas valve that opens or closes to feed gas to the burner. That gas valve is in turn powered by a low-voltage transformer that is electrical. Still I don't think a thermocouple itself would be affected by a power surge or outage.

Your question does suggest a bigger problem here, one that unfortunately leaves me telling you to spend money to hire a licensed electrician to examine the whole electrical system in your home for SAFETY!

Look: even if I were the dope who plugged too many things into one electrical receptacle or circuit in your home, at the worst that should have tripped a single circuit breaker or blown a single fuse that is supposed to protect that specific circuit from overloading - thus trying to avoid an electrical fire.

So if overloading an individual circuit doesn't trip that circuit's breaker, and if instead the main breaker or fuse blows, turning off all power for a time, that sounds to me as if something is wrong with your electrical panel.

Or we're wrong and it was a coincidence and there was a power surge in the whole neighborhood where you live - ask your neighbors if that occurred. If it didn't then there is indeed a problem to find in your home, and until it's found the home is not really as safe as it should be.

Keep us posted.

On 2017-01-15 by Marilyn Mitchell

My Grandson was working on his car, and using a light extension cord to use an electrical tool of some kind PLUS a drop light.
I had warned him to be careful & not to plug in but 1 thing at a time. But we lost power to our complete house for a few minutes and then it came back on, so I knew he had not listened to me.

We live in a single wide Mobile Home. The next day long story shortened, I noticed the pilot light to our furnace was out & would not lite.
I called the repair person, & it was the Thermocupler that had went out, & he replaced it, & furnace is working fine.

My question is, can power bumps like I had, can they cause problems with appliances in our home, even say my Well, as now MY PUMP in our well house is acting up >> the water pressure is very low & I can tell something is very wrong. We just had the pump replace in 2013, and they said we never had to worry about running out of water so I know it is not that. I lost my husband last year 2016, so I could use some advice, Thank You Kindly In Advance, for some advice, Marilyn

 

On 2016-12-19 by (mod)

Also if that electrical receptacle or receptacle that you are installing are in a garage, you probably are required to install GFCI protection on the circuit or at the receptacles.

On 2016-12-19 0 by (mod) ground wire details

Karl,

Since I don't understand your situation exactly, I feel comfortable giving a general answer.

Each of your electrical circuits will have its own grounding conductor. Within a single electrical box we connect all of the ground wires in common typically with a shrimp or clamp connector. If the box is a metal box we also connect those wires to the Box using a clip or grounding screw. In addition you will need to leave one or more of the ground wires of that connected group long enough to connect to the ground screws on switches and electrical receptacles.

However I have other concerns about what you are describing. One is that with 12-2 or 12 3 wire you may find that the boxes that you are using are not large enough. Be sure to check the number of wires in the box and the wire size and box cubic inches against the box sizes in the wiring tables in the National Electrical Code of equivalent depending on where you live.

Also you may be required to obtain a building permits and have code approval inspections. I know that's more trouble, but think of it as a free fire/safety inspection by an expert.

I'm always nervous about two separate power circuits running into a single electrical box, even where permitted, having seen people switch off just one of the circuits and then begin work and find themselves getting shocked.

On 2016-12-19 by karl

i have two recp,s in one box both are wired 12-2 and separate circuits one for lights 15 amp. . 20 amp for garage door opener do i need separate ground wire for each one to box or tie all together

On 2016-12-06 by Anonymous

Pushmatic Circuit Panel: 3 wires; black wire to 20 amp breaker / red wire to 15/15 amp breaker, and white to ground. After several years the 20 amp breaker now trips when 15/15 breaker is on, and vise-versa. Could one or two breakers now be defective?

On 2016-11-26 by (mod)

Is it a gas or electric dryer. Surely if electric it's got a dedicated 240V circuit, right?

Overloaded circuit, wiring error, loose connection?

On 2016-11-26 by (mod)

Really posting

AUTHOR:Gabriel (no email)
COMMENT:I bought a new Samsung washer and dryer. Tube washer works fine, but when I turn on the dryer, the power goes our in the bedroom outlet and the dry turns off, but no breakers trip. The power goes out for only a moment. What could it be?

On 2016-11-22 by Anonymous

derating solar wiring in panel

On 2016-10-14 by steve warlow

Ideal logic combi boiler 35 keeps tripping when wired on the mains circuit going through the 3 amp fuse to feed the boiler, have had transfer valve in boiler replaced that may have been the problem, also had electricians check the fuse switch which feeds boiler,to make things more difficult is if you hard wire the boiler with a extension lead to a plugged socket it runs fine which says that there is nothing wrong with the boiler, could it be cross polarity and if so how do you fix it

On 2016-10-12 by doug

having a prob. w/ceiling lite fixture. on switch hav a bk & white. probe bk&white together, nothing. bk. to grd. nothing. white to grd. hot. hook up on switch no power. lite fixture has 3bk. tied together, 2 whites tied together, & 1 black. fixture connected to double white & single black. switch on nothing. help please.

On 2016-09-28 by (mod) -

Anonymous:

You'll need to visit your local building department, describe the work that you plan, find out what permits and approvals are required and typically, file an application using local forms.

Lisa:

You will need to contact your local building department, as to speak to the electrical inspector. Depending on where you live your state or province may use an independent fire underwriters-certified electrical inspector or a local electrical inspector may do the job. Note that not all jurisdictions permit homeowners to do their own wiring.

On 2016-09-26 by Anonymous

Hello or get a homeowner permit?

On 2016-09-26 by LISA

HELLO,

LEARNED ALOT BUT IF COMPLETING A MOBILE HOME RE WIRING UPGRADE HOW DO I GET IT INSPECTED UNDER HOMEOWNER

On 2016-08-01 by (mod) -

Kelly:

For a code compliance inspection, call your local building department. That's who performs that work. It's a good place to start and may not cost you.

For an estimate of the cost of required electrical repairs, you'll want to hire a local licensed electrician - listed by phone book or by better business bureau, or by searching for "Licensed Electricians + city and state or province name"

On 2016-08-01 by Kelly

Where can I find an electrical inspector for my mobile home

On 2016-06-27 (mod) -

Normally a 200V main panelists providing 240V
OR nominal 220v as you suggested.

Provided you have room in the panel for two 2-pole 220V breakers you can feed 2 229V circuits.

Of course we don't know

. what else is in the panelso we don't know if you're overloading it

. What parity your 2 new circuits need.

It's amparity that determines wire size, to which you add effects of long runs that in turn means going to a larger wire size to avoid voltage drop and overheating problems.

Sorry but with no data we c a nt be more specific.

On 2016-06-27 by mike

will I be able to run two 220 circuits off a 200amp breaker box and go 300ft to a out building . what size wire would be best to run over head.

On 2016-06-19 by (mod) -

Daniel

The first breaker you describe is probably a GFCI (ground fault circuit interrupter) or an AFCI (arc fault circuit interrupter) that adds additional safety features to the circuit that it protects, by detecting small current leaks (GFCI) or small arcing at connections (AFCI) in the circuit, and in the event of those, shutting down the circuit to protect the occupants from shock or the building from fire.

These are added features above and beyond the basic function of circuit breakers to detect overcurrent and shut down before the circuit overheats (a fire risk).

If you have wall plugs (electrical receptacles) showing just 60V in a country that runs 120/110V on those circuits there is a wiring error, perhaps a short to ground or something else. You should turn OFF those circuits until an electrician can find and fix the trouble - the worry is that there could be shock or even fatal electrocution hazards.

Search InspectApedia.com for GFCI GROUND FAULT CIRCUIT INTERRUPTORS and for AFCI ARC FAULT CIRCUIT INTERRUPTORS to read details.

Keep me posted

On 2016-06-19 by Daniel

Hello,i have an older single wide mh,two questions if i may,the first in the panel there is a breaker that has the black and white directly to it then a white pigtail out of the breaker to the neutral bar this breaker has a test button on it also. the other question is some wall plugs are showing 110v while others are at half the voltage. thank you

On 2016-04-06 by Allen

Thank you...

On 2016-04-03 by (mod) -

IN this order I'd check:

1. the bulb: take a bulb that's known to be working - you saw it lit on a fixture - and try it in the fixture - if it won't light then try it again in the fixture where it was working to confirm the bulb is still good, OR try the exsting light's bulb in an indoor fixture - we want to avoid looking dumb because we had a bad bulb

2. check that all relevant switches are on

3. check for electrical power right at the fixture, using a DMM, VOM, or neon tester - WATCH OUT: if you don't know how to do this use an electrician as you could be killed.

4. If the fixture has power and the bulb is good, someone who can follow the wires can bypass the sensor - if the fixture lights, replace just the sensor.

5. If the fixture still won't light check for a cracked or damaged bulb socket

6. last resort: change the whole fixture along with its sensor

On 2016-04-03 by Freezing Cold

Without warning, our outdoor dusk to dawn light stopped working Tried cleaning the fixture's sensor & changing floodlight bulbs, but that didn't help. Any ideas or suggestions? Or is this 3-year old fixture a goner? Thanks.

On 2016-04-02 by (mod) - The GFCI can keep tripping if

Allen, GFCI's belong in bathrooms, I agree, as that's an area of high shock risk (electrical receptacles close to plumbing fixtures and water).

The GFCI can keep tripping if

- it's mis-wired

- there is a short circuit in the electrical system or in something plugged in on the GFCI-protected circuit

- the device is damaged or failing

- the device is in a too-wet, too-humid area

- something else I"ve not remembered

It's common to wire additional receptacles or sometimes even lights "downstream" from the GFCI. That means that if the GFCI trips everybody down-the-electrical-river (ok further on in the circuit) will get turned off too.

If you re-set the GFCI and it doesn't stay re-set, you need help from an electrician to find and fix the problem.

But you can start by unplugging everything that's plugged into that electrical circuit, from the GFCI in the bath and downstream from it.

Then try re-setting the GFCI (just press the reset button); if it re-sets you can try plugging in each thing you had on the circuit. Probably one of them is the culprit.

If it does not re-set or won't stay reset, the problem is in the device, the circuit, or in water.

On 2016-04-02 by Allen

1992 double wide it had a gif in the bathroom that kept triping. and when it did it shut off the pluges in my bathroom 60 feet away,so I change the plug to my to none gif, and I would let the barker box trip if needed, it work good untill my wife plug in the vacleaner into that switch....

Now i have no power there or in my bathroom plugins. The breakers did not trip. any thouths on my problems.

Question: main breaker is not switching off power to the electrical panel

(Sept 1, 2011) Tim Schwartz said:

I have a zebco panel and when i turn off the 100amp main i still have power, any advice?

Reply:

Tim,

Watch out: in any electrical panel, if you still have power when the main disconnect is in the "OFF" position then this is a VERY dangerous condition as you cannot, using normal homeowner controls, turn off electrical power in an emergency, and more, it is likely that the main disconnect is not going to trip on a large overcurrent and so is not protecting the equipment and building from an electrical fire.

The brand "Zebco" is not one I know, and I'd like to see photos of the equipment and all identifying labels and markings so that we can research the brand further. Use the CONTACT link found at page top, left, or bottom to send us photographs. (Zebco is a brand of fishing tackle).

On a few occasions I've encountered electrical wiring connections at which power was brought into an electrical panel from more than one feeder, wired or I should say "back-wired" to the panel bus through a subordinate circuit breaker. For example if someone installed a local or backup electrical generator and connected it to back feed the electrical panel through another breaker (without a proper isolation switch) you could find that the panel is energized even though the main disconnect was off.

Panel backfeeding without an isolation switch to prevent both main disconnect and backefeed source from powering the panel at the same time is improper and unsafe and would need to be connected.

Presuming that you don't have a back-fed panel from a second electrical source then you immediately need a licensed electrician to replace the faulty circuit breaker or if necessary the panel.

Question: When were houses commonly built with split outlets/receptacles?

(Oct 12, 2011) Maria S said:

When were houses commonly built with split outlets/receptacles? I am doing research to find out how many houses in the US may not have them.

Reply:

Interesting Question, Maria.
My opinion based on research is that split receptacles would not have seen widespread residential use before 1965-1970 - I continue to research the topic.

I've posted my preliminary research and opinion above in this article

Question: how to identify the electric panel ampacity and voltage

(Feb 7, 2012) Bill R said:

in an apt bldg, each meter for each of the 50 apts contains an individual electric meter with a disconnect below it that appears to 'span' over 2 breakers but the 'bar' that spans over the 2 breakers reads 60 - does this mean that this is a 60 amp electric service?

Reply:

Bill, it sounds as if you're describing a 2-pole 60-A main breaker - that's normally giving 240V service and 60 Amps as marked on the breaker.

Question: using a grid inverter

(Aug 21, 2012) inetdog said:

One notable exception to the limitation of one power source at a time is the use of a grid-tied inverter for solar PV generation. The grid-tied inverter is designed to synchronize to the utility voltage, and will only output power when the utility grid is present.

Question: open neutral wire at receptacle

(Nov 30, 2012) gary said:

i have a open nuetral at home showing at the recepacle i used a plug in tester and it shows that,the basement is finished no drop ceiling and upstairs as well where can i go from this point.
Thankyou......gstoronto@aol.com

Reply:

You need to trace the circuit wiring, Gary. There are quite a few devices that can help you do that - check online or at your local building supplier.

Question: apartment fire, aluminum electrical wire: does it need to be replaced?

(Mar 7, 2013) charles.parizeau@sympatico.ca said:

A fire occured in a unit of an apartment building. all interior finished on the walls had to be replaced, the electrical wiring is aluminum. Does the wiring needs to be replaced with copper to meet the building code?

Reply:

Charles, building codes don't explicitly require replacement of aluminum wiring though there are code sections that allow that interpretation.

Watch out: I'm not an expert on repairing fire-damaged wiring but it seems to me the concern would be that the wiring insulation has probably been compromised - made unsafe - by exposure to the heat of the fire. Therefore it's likely that an inspector would want it replaced regardless of whether it had been originally copper or aluminum conductor wiring.

Question: using an electrical tester to find hot wires

(Apr 3, 2014) gm1761 said:

I'm using the usual electrical tester to confirm if some areas where there once light fixtures are "hot." Most of my readings are correct as the tester works on installed fixtures and outlets. My problem arises when the tester does not show a hot area when the switch and light are both on. Any reasons for this?

Reply:

GM I can't quite figure this one out. The only thought that occurs to me is a wiring snafu; if we connect a neon tester between two hot legs on the same phase (rather than a hot leg and a ground or neutral) it will now show current flow.

Question: power off in one room

(May 4, 2014) Anonymous said:

One whole room does not work

Reply:

Anon if power is on for all circuits at the electrical panel then an electrician will trace the circuit to find the open connection. Meanwhile turn off that circuit to be safe.

Question: two wire circuit, no ground at switch boxes

(June 3, 2014) DanW said:

I have a two switch box with two wire no ground that controls the lights and ceiling fan. The light works but the ceiling fan does not. I have just installed a new fan and still have the same issue. I changed the switch for the fan to a new one. I am at a loss as to why the fan will not work. I have checked all connections and they are tight and secure. Help!

Reply:

Dan,
Typically the two wires to a switch are simply allowing the switch to interrupt the hot wire to a device. You also need a 3rd wire in the box, the neutral wire, to run the fan.

A DMM or VOM can confirm which are hot and neutral wires.mbe sure to reasd our article on using DMMs VOMs safely

By the way, the switch itself probably includes a grounding screw and should be grounded - so the wiring may be incomplete and not safe if you're missing proper grounding.

Question: trouble tracing wires in 24 pin cable

(June 24, 2014) Michael said:

Have a cable with 24 pin plugs on each end. Have good continuity from each pin from plug A to plug B; however, pin x and M are shorted together on Plug A but on Plug B pin x and M read open. How is that possible?

Reply:

Perhaps an internal short between two wires in the cable or between 2 pins in the plug. On some cable assemblies individual wires may be deliberately joined as well, depending on the application.

(June 24, 2014) Michael said:

Shouldn't the short be able to be seen from either plug A or plug B?

Michael I surely don't have a clear idea of what you are testing.

In general if two wires are shorted together you will see continuity on both, but if you put a test current on A and A is also shorted to B you will probably see the current or signal on BOTH A and B at the other end of the cable.

...

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