Other Uses for the NCB PlugUpdated 11 days ago
The NCB Plug can do more than support grounding products. It can also help with contact current testing, spectrum analysis, reducing grounding loops, certain workstation setups, and troubleshooting some appliance-related ground noise.
What else can the NCB Plug be used for?
In addition to its main grounding-related benefits, the NCB Plug has several other technical uses. These uses are mainly for testing, measurement, and reducing unwanted electrical noise in certain setups.
1. Representing the body during contact current testing
The NCB can be used to simulate the body during contact current measurements. The article explains that instead of holding the meter lead and using your body as the contact point, you can plug the black lead into the NCB and set the dial to represent body resistance. Then you place the red lead on the object being tested.
The article notes these example resistance ranges:
- Around 300–500 ohms for wet conditions
- Around 1,000–2,000 ohms to represent the body in many test setups
- Up to 10,000 ohms for dry, ideal conditions with no frequencies present
2. Spectrum analysis on a grounding conductor
The NCB can also help with spectrum analysis when measuring noise on a grounding conductor. The article explains that this type of measurement can be difficult with a differential probe unless you use an NCB. In that setup, the red lead attaches to the grounded item, while the black lead is connected through the NCB so the frequencies on the grounding conductor can be seen more clearly.
3. Helping remove grounding loops
The article says the NCB can help reduce a grounding loop when two or more appliances are connected together but powered and grounded from different outlets. In that situation, using the NCB on one of the appliances may help remove the loop.
The article also includes an important caution: always measure for a possible rise in electric field if the appliance loses its usual ground reference. It also notes that appliances should ideally be grounded in one place, from one source, not two.
4. Reducing noise from certain appliances
If an appliance is leaking current or dirty electricity noise onto its grounding conductor, the article says the NCB Plug can be used to reduce that noise on the grounding system.
However, the article also warns that this may increase the electric field around the appliance and may increase contact current exposure if the appliance is touched. Because of that, the article says appliances with metal frames or handles are best kept solidly grounded with no added resistance on the grounding conductor.
For this type of use, the article recommends starting with the dial turned all the way to the left. It says that setting allows as much current through as the NCB will allow while still filtering the grounding conductor, and provides about 14 ohms of resistance. From there, the dial can be adjusted to find the preferred balance between noise reduction and electric field exposure.
5. Workstations with grounded wrist straps
The article also mentions a workstation use case. If someone must be tethered to a grounded wrist strap at work to prevent static buildup and discharge, the NCB may help reduce current through the body, slowly discharge static buildup, and maintain a ground-fault path.
6. Use with a GFCI outlet
The article recommends using a GFCI outlet with the NCB in all applications. It explains that a GFCI outlet adds important ground-fault protection and improves safety.
Frequently Asked Questions:
Can the NCB be used for testing, not just grounding products?
Yes. The article describes technical uses such as simulating the body during contact current testing and helping with spectrum analysis on grounding conductors.
Can the NCB help with grounding loops?
Yes. The article says it can help reduce a grounding loop when connected to one of the appliances in the loop.
Can the NCB be used with appliances?
In some cases, yes. The article says it may help reduce noise on the grounding conductor of an appliance, but it also warns that this can increase the electric field around the appliance.
Should I use the NCB with a GFCI outlet?
Yes. The article recommends using a GFCI outlet for added ground-fault protection.