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What does a background reading with hot ground mean?



“Hot and ground reversed” is just one of the many diagnostic readings that can be indicated by an outlet / container tester (Figure 1). It usually indicates the absence or malfunction of a neutral conductor somewhere in your system.

If you get a Hot / Grd. Reverse reading, check your neutral leaders. One of them may be burnt out and require replacement or simply loose in need of a mild tightening.

However, a few different types of situations can trigger such a reading. To get a more complete picture of the container̵

7;s test results, check out the information below.

power take-offs with explanations

The tester is simply an instrument that reads the relationship between the hot, neutral and ground wires at specific sockets in a circuit and a faulty container will not necessarily be reflected in all other sockets in the circuit.

When the “correct” reading is not displayed with the correct light sequence on the container tester, the lights that will come on will indicate the probable cause in relation to the faulty wire, caused by broken or mixed wires, or wires connected to the wrong terminal screws. However, the fault may be at another location within the circuit and some tracking may be required along the line to find its origin. When doing electrical work, there is also the possibility that a combination of several faults results in misdiagnosis. The following is a progressive write-up that describes all possible diagnoses and all possible causes.

figure 2 describes all sockets in the following circuits, shows two sockets, each with three openings – a short hatch connected to the hot terminal, a longer hatch connected to the neutral terminal (provides the return route) and the semicircular ground opening matched to the green ground terminal but also connected to the metallic enclosure box.

1. Open ground (Gnd)

Figure 3 shows two circuits with the same problem but in different places. Although the defect is virtually unnoticed without a tester, a break (or loose connection) in the ground wire at any of the sites may not prevent a device from working when connected to it, but it does pose a serious risk to electrical protection from sockets # 2 in circuit A and from both containers in circuit B a short circuit would occur while the open ground position exists.

circuit diagram

An “open ground” reading is often the result of someone forgetting to connect the cable to the green terminal screw or a broken ground wire, causing the following results –

1.1-A multimeter that does not show any voltage between the Hot and Ground terminals at outlet no. 2 in circuit A and at neither outlet in circuit B but reads 120 volts at outlet # 1 in circuit A.

1,2-The multimeter that shows 120 volts between Hot and the white neutral contacts on all sockets.

1.3-A socket tester lights that show “Open ground” on socket # 2 in circuit A and both sockets in circuit B, and “Correct wiring” when connected to socket No. 1 in circuit A.

A word of caution – A physical connection must also ground the enclosure to the container ground terminal.

2. Open Neutral

IN Figure 4, circuit C has current in outlet no. 1 but none at outlet # 2 and there is also no effect in circuit D. Check for a broken or loose wire connection on one of the white wires at the indicated points (inside the red star) in circuits C and D.

circuit diagram

Testing of the containers will result in any of the following:

2.1-No voltage shown between the hot and neutral terminals in either outlet # 1 or # 2 in circuit D or outlet # 2 in circuit C, but the multimeter would read 120 volts at outlet # 1 in circuit C.

2.2-A 120 volt reading between hot and ground at one of the outlets in both circuits C and D.

2.3-A 120 volt reading between Hot and Neutral only at outlet No. 1 in circuit C.

2.4-The socket tester which shows an “open neutral” on socket no. 1 in circuit D as well as on socket # 2 in both circuits C and D, and “correct connection” when it is connected to socket no. 1 in circuit C.

Note: A device works on socket no. 1 in circuit C but not on any of the other sockets.

2.5-In a special case, “Open Neutral” can easily become a “Hot and Ground Reversed” which is highlighted in the section “5 – Hot & Gnd Rev”.

3. Open hot

Without lights on the tester at outlet No. 2 in circuit E or anywhere in circuit F, with the exception of outlet No. 1 in circuit E which tests “Correct”, the Hot line is open past the last outlet that is lit – it may even be on the discharge cable on that socket – or before outlet no. 1 in circuit F (figure 5).

circuit diagram

4. Hot & Neutral Reversed

Figure 6 shows two circuits with an unconventional mixture of wires at certain outlets. This often happens when you add containers to existing circuits, and it gives voltage (although it is uncertain) to all containers, along with the following results—

circuit diagram

4.1-The socket tester only shows “Correct wiring” on socket no. 3 in circuit G and socket no. 1 & 4 in circuit H.

4.2-A multimeter shows 120 volts over the hot and neutral terminals on ALL sockets.

4.3-A multimeter shows 120 volts between the Hot and Gnd terminals on outlet # 3 in circuit G and outlet # 1 & 4 in circuit H.

4.4-The multimeter does not show any voltage between the Hot and Gnd terminals on outlet no. 1 & 2 on circuit G and outlet no. 2 & 3 in circuit H, but 120 volts between the neutral and Gnd terminals which make these outlets deadly dangerous by placing a voltage on each grounded part of all appliances connected to it.

5. Hot & Ground Reverse

This contradictory statement means that the earth wire is activated with 120 volts while the hot wire is earthed, which would create a short circuit! But as illustrated in Figure 7, there are some wiring configurations that, without shorting, can cause the container tester to give a “Hot & Gnd reverse” result.

circuit diagram

5.1-Such a situation can occur as in Figure 8, with an open neutral line upstream of the faulty container (towards the panel) while a load such as a lamp is connected to that container or another container downstream (further down the line). The open line would prevent the current from flowing, so that the lamp does not light up. The light can therefore not cause a voltage drop but creates a connection between the outlet’s hot and neutral slots that flow to the two at 120 volts, which the tank tester identifies as “Hot & Ground Reverse.”

circuit diagram with hot ground reversed

5.2-A “bootleg” ground position is often found in older installations before safer electrical installations that included a ground wire existed. In the absence of the ground cable in the circuit, the ground terminal of the container is connected to the neutral – which is a code violation. A standard socket tester cannot detect a Bootleg chip that reports it as properly connected or “correctly”.

However, the exercise is unsafe and less dangerous than “reverse bootleg”, where the hot and neutral wires are mixed up and end up on the wrong terminals with the ground terminal connected to Hot instead of the neutral wire (Figure 7) and create the same hazard as described in section 4.4.

So armed with all this information and a container tester, you are now ready to make your home a safer place.




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