Electrical Unit 7 - Principles of Home Inspection Systems & Standards 3rd Edition

Knob-and-tube wiring was commonly installed without junction boxes. T/F

True

Outlets should be close to basins. T/F

True.

What would two wires usually mean in a 240V service drop?

120-volt service.

What size wire is found on most general-purpose outlets for lights and receptacles?

14 gauge

The most common wire size for branch household circuits is _____ gauge.

14 gauge.

Wires run directly from the service box to the branch circuits. T/F

False

List for common problems with knob-and-tube wiring.

Connections not in boxes / brittle wire, insulation, or sheathing / wire buried in insulation / fused neutrals.

One smoke detector is needed in each home, near the kitchen because that's where most house fires start. T/F

False

All service entrance conductors must be attached above roof level? T/F

False.

All service entrance conductors must be in conduit? T/F

False.

Load calculations are part of a home inspection? T/F

False.

Subpanels must be immediately adjacent to the main panel. T/F

False.

The drip loop is typically part of the service drop? T/F

False.

The drip loop should be as close to the roof surface as possible? T/F

False.

The wire size for the service drop must equal the wire size for the service entrance conductors? T/F

False.

There can be up to 10 throws to disconnect all the electricity in the house. T/F

False.

Typical distribution panels have 60 circuits. T/F

False.

You are allowed to ground to the gas piping. T/F

False.

Does knob-and-tube wiring have a ground wire associated with it?

No

The grounding systems are connected to the house neutral at the _____.

Service box.

Distribution panels are also called _____. (List six other names if you can)

Service panels, panelboards, auxiliary panels, sub panels, fuse boxes, breaker panels.

List six problems found with wires in panels.

Sheathing not removed / overheating / loose connections / damaged / not well secured / wires crossing bus bars / abandoned wires in panel

Describe how you would test a GFI receptacle during an inspection.

Use a conventional circuit tester and operate the test button on the receptacle.

Do we normally shut off the power when looking at an electrical system in the house? Why or why not?

We do not shut off the power. This would be a significant inconvenience to the occupant.

What are the issues on running wire through steel studs?

Wire may be damaged by sharp edges of steel studs. Wires passing through holes should be protected with grommets, for example. Wires running parallel to studs should stand off the studs.

Can an outlet be protected by a ground fault interrupter without it being apparent?

Yes, all outlets downstream of a GFI outlet will be protected.

Why are should be _____ inches away from the edge of studs.

1.25 inches. (one and one quarter inch)

What size copper wires are adequately protected by each of the following? 1. 15-amp breakers 2. 20-amp breakers 3. 30-amp breakers 4. 40-amp breakers

15-amp breakers - 14 gauge 20-amp breakers - 12 gauge 30-amp breakers - 10 gauge 40-amp breakers - 8 gauge

Roughly 999 out of 1000 houses have _____V available (insert a number).

240

What is the largest single-phase service that you're likely to find in a home?

400 amps.

What size copper wire would you expect to find on the service entrance for each of the following?

60-Amp Service 100-Amp Service 200-Amp Service 60 amps: 6 gauge 100 amps: 4 gauge 200 amps: 2-0 gauge

A grommet is _____.

A fitting that protects cable from the sharp edges of steel studs.

Wires should not be run on wall surfaces without _____.

Mechanical protection.

What is a split receptacle?

A split receptacle has the top part of the outlet on one circuit and the bottom part on a different circuit

Why should heat lamps not be located over doors?

A towel thrown over a door might be ignited by a heat lamp.

List clearances above ground, swimming pools and roofs.

Above roadway: 18 feet Above driveway: 12 feet Above flat roof: 8 to 10 feet Above sloped roof: 18 inches Away from water in swimming pool: 22.5 feet in any direction. 3 feet above sloped roof with pitch greater than 4 in 12 Above walkway: 10 feet

What is meant by open splice?

An open slice is a connection that is not made inside of junction box.

What is the problem with running wire across the top of the attic ceiling joists?

Because they are not visible and may be stepped on.

List five common areas of water penetration into service entrances.

Conduit joints Mast head Roof flashing Meter base House entry

List three commons problems found with aluminum wiring.

Connectors not compatible with aluminum / no anti-oxidant grease on stranded wires / overheating.

List two different branch wire materials you might see.

Copper / aluminum

Give 4 examples of damage wire.

Cut or pinched / chewed on by animals / burned wire / wire with brittle or cracked insulation

List 13 common lighting problems found in houses.

Damaged / Loose / Overheating / Inoperative / Obsolete / Not grounded / missing / poor stairway lighting / conventional lights being used in wet areas / improper recessed light used in installations / improper closet lighting / heat lamps over doors / isolating links needed on pull chains / hanging light fixtures above a bathtub.

List 17 common branch circuit-wire problems?

Damaged / Wires run under carpets / overhead wires not stranded / not well secured / loose connections / opens splices / wires too close to ducts, pipes, vents, chimneys, flues / wires too close to edge of studs or joists / wires run through steel studs without protection / exposed wires on walls or ceilings / exposed wires in attics / cable used outdoors / buried cable not rated for buried use / household wire used as extension / undersized wire / improper color coding / abandoned wire.

List four common problems with switches.

Damaged / loose / overheating / inoperative.

List 13 common receptacle problems.

Damaged / loose / overheating / ungrounded outlets / open neutral or open hot connections / reversed polarity outlets / inoperative / wrong-type receptacle / no GFIs / worn receptacles / broken pin or blade in slots / not enough receptacles / too far from basin.

List seven common junction box problems.

Damaged / missing / loose / not grounded / cover loose or missing / crowded / concealed boxes.

A fused 200-amp service has two 100-amp fuses in the service box? T/F

False

All junction boxes should be concealed. T/F

False

If you can't read the size of the fuses in the service box, you should remove them to try to get a better look? T/F

False

How should the feeder wires to a subpanel from the main panel ideally be protected?

Fuses should be provided at the main panel.

What are the two functions of earth grounding systems?

Grounding systems can help dissipate electricity from lightning / avoid the buildup of static electricity.

What is the difference between Insulation and sheathing?

Insulation is around the individual wires, and sheathing forms the cables by wrapping around the insulated wires.

What is meant by linking in multi wire branch circuits?

Linking means that the fuses or breakers for multi-wire branch circuits have to be shut off in pairs.

List six destinations where ground wires can terminate.

Metal water supply pipes / metal rods driven into the ground / wires buries in the footings of buildings (UFER ground) / buried grounding plates or rings / the frames of metal buildings (not common in houses) / metal well casings.

When was aluminum wire used?

Mid 1960s to 1970s

What is the advantage of a 240 V circuit?

More electricity can flow at lower average ratings.

List 4 common problems found only with breakers.

Multi-wire circuits not linked / too many breakers / wrong breakers and panel / loose breakers

Describe three different cable types you might see.

NM, Romex, Loomex / UF / BX (AC-90), armored cable / Knob-and-tube

List 11 common problems with service entrance conductors.

No drip loop No mast head Masthead not weathertight Service entrance ires too close to roof Mat or conduit bent Mast or conduit rusted Mast rotted (if wood) Mast conduit or cable not well secured Mast conduit or cable not weathertight Conduit or cable not well sealed at house/wall penetration Cable frayed, damaged, or covered by siding

List 13 common problems found with grounding systems.

No grounding / Ground wire attached to plastic pipe / ground wire after meters and valves with no jumper / spliced ground wire / poor connection / ground connections not accessible / ground rod cut off / corroded ground rod / undersized ground wire / neutral bonded to ground wire at service box / natural wires not bonded to ground wire at service box / service box not bonded to ground wire / no ground in sub panel feeder wires

Should the neutral and the ground wires be bonded together at the subpanel?

No. Because electricity may flow through the ground wire under normal circumstances. The ground wire should be reserved for emergency situations.

Implications of an undersized service include which of the following? Shock hazard Fire hazard Shock and fire hazard Melting insulation Nuisance shipping of the main fuses or breakers

Nuisance tripping of the main fuses or breakers. Note: unless there is overfusing as well, in which case there is a fire hazard.

List 16 conditions that maybe found in all panels.

Obsolete and/or fused neutrals Damaged panels or components Loose or missing door openings in panel Panel too small Overheating Rust or water in panel Loose panel Inappropriate support material Circuits not labeled Panel crowded Poor access Upside down Not suitable for aluminum wiring Poor location Exterior panel not weathertight

Where is the antioxidant grease typically used?

On strand aluminum wires.

List nine common problems with service drops.

Overhead wires too low Overhead wires too high Damaged or frayed wires trees or vines interfering with wires Wires too close to doors or windows Wires not well secured to the house Poor connection between service drop and service entrance Inadequate clearance from roofs Service lateral problems

Is the service drop overhead or underground?

Overhead.

What are the implications of oversized breakers?

Oversized breakers will allow wires to overheat without tripping.

List 17 common conditions you might find in a service box.

Poor access or location / loose / rust or water in box / unprotected opening / inappropriate support material / damaged parts / overheating / incorrect fuse or breaker size / box rating too small / service entrance wires exposed in the house / poor connections / illegal taps / neutral wire bypasses service box / fused neutral wire / fuses upstream of disconnect switch / obsolete box / exterior box not weathertight / bot not rated for aluminum.

Lists two functions of the drip loop.

Prevents water entry into the conduit or service entrance conductors Shows that the service drop wires are not straining the splices

Abandoned wire should be _____.

Removed.

What caused the problems with aluminum wiring (list at least 3)?

Tends to creep out from under the terminal screws Forms corrosion (oxide) that is an electrical insulator Is softer than copper and easier to damage when working with the wire Aluminum wire was, in some of the earlier material, a low-quality wire prone to weakness and breaking.

List three methods of securing wire ends.

Terminal screws / push-in connectors / solder less connectors

Are service laterals overhead or underground?

Underground.

Describe how knob-and-tube wiring is visibly different from modern cable.

The black and white wires are separate, so the circuit wires usually run in pairs. There are ceramic tubes protecting the wires where they pass through joists or studs. There are ceramic knobs where the wires change direction.

Explain the problem with reversed polarity.

The collar of a light fixture maybe energized, increasing the risk of electrical shock when changing a lightbulb.

How would you identify aluminum wiring?

The conductor itself is silver colored. The sheathing usually has the word aluminum, alum, or al.

The grounding electric conductor may also be called _____.

The ground wire.

What is the implication of a panel that is too small for the service?

The panel may overhear.

Which of the following is a reliable way to identify the service size? The size of the service drop wires The distribution panel rating The service box rating The service entrance conductor size The service entrance conduit size

The service entrance conductor size

The service entrance conductors run from the _____ to the _____.

The service entrance conductors run from the service drop to the service box.

Explain why fused neutrals are bad idea.

These are dangerous because the fuse on a neutral side only blows. The circuit may not work, but there may be voltage throughout the entire circuit.

Roughly 999 out of 1000 houses have _____ service entrance wires (insert a number).

Three

How many wires would you typically find in a 240V service drop?

Three wires.

What would four wires mean in a 240V service drop?

Three-phase electricity.

From the point where the ground and the neutral wires connect, there are two paths to ground. What are they?

Through the natural service wire or through the grounding electrode conductor to the water pipes or ground rods.

Which of the following is a safety concern: A fuse that is too big, or fuse that is too small?

Too big.

The red and black wires of multi-wire circuits should be on separate bus bars. T/F

True

Aluminum is an acceptable service entrance conductor material? T/F

True.

The service box can be inside, outside, or in the garage. T/F

True.

This service box may stand alone or be combined with the distribution panel. T/F

True.

How are lights tested?

Turning them on and off by their switches.

What does the term double tap mean?

Two wires are connected to a single terminal

Which of the following is a safety issue? a. The main fuses have a lower rating than the service entrance wire b. The main fuses have a higher rating than the service entrance wire c. The service box has a higher rating than the service entrance wires d. The service box has the same rating as the service entrance wires e. The distribution panel has a higher rating than the service entrance wires

b. The main fuses have a higher rating than the service entrance wire.