RF Bonding questions

[videobruce]

This is bonding, not grounding questions.
I have read thru;
ARRL General Class License Manual Chapter 5.5
ARRL Handbook Volume 5 Chapter 22.1.8
publications on RF bonding and I have a few questions on what should be bonded and what doesn't have to be.

Do these have to be bonded?;
1. Electrical electronic equipment in non-metallic (plastic) enclosures,
2. PC related, monitors, printers, copiers, Laptops (other than Towers in a metal enclosure),
3. Network equipment; Routers, VOIP adapters, Switches etc,
4. Equipment in metal enclosures that are DC powered thru a DC wall adapter, CCTV DVR,
5. Scanner receivers connected to a grounded roof antenna,
6. Test equipment in plastic enclosures with earth ground; Spectrum Analyzers, Scopes, etc,
7. Metal file cabinets or desks (non metal top, metal drawers),
8. Telephones, lamps with metal bases, metal enclosed Bench Power Supplies,
9. Lastly a Dual band 50w (almost always set for 5w out) mobile and/or a metal case PS.

All of this is in a 2nd floor room in a 'double' home with a #6 gauge ground wire tied to the electrical ground via two 8' ground rods. The AC outlet is grounded where everything gets run to thru power strips.

 

[videobruce]

Taking from here; The Ultimate Guide To Grounding Straps And Bonding For Ham Radio - Amateur Radio Zone

3.1 What is bonding?
Bonding refers to the process of creating electrical connections between metallic components to establish a common ground and minimize the potential for differences in voltage potential. In ham radio, bonding involves connecting various equipment, structures, and antennas to a common ground plane or ground system. By doing so, bonding helps eliminate voltage potential differences that can contribute to interference and ensures consistent performance and safety of the radio system.
3.2 Why is bonding necessary in ham radio?
Bonding is necessary in ham radio for several reasons. Firstly, it helps in reducing the risk of electrical shock and equipment damage by establishing a path for electrical currents to flow safely to the ground. Secondly, bonding aids in minimizing interference caused by voltage potential differences between different equipment and structures. By bonding all the components in the system to a common ground, it ensures they are at the same reference potential and reduces the potential for electromagnetic interference. Lastly, bonding plays a crucial role in providing lightning protection by promoting the safe dissipation of lightning-induced currents.
3.3 Techniques for effective bonding
To achieve effective bonding in a ham radio setup, several techniques can be employed. One common method is to bond all metallic equipment, such as transceivers, amplifiers, tuners, and other components, to a common ground bus or ground bar. This ensures that all equipment shares the same ground reference and reduces the potential for ground loops. Additionally, bonding antennas, towers, and other structures to a proper ground system is essential for both safety and performance reasons. Bonding conductors should be of sufficient size and made of materials with good conductivity to avoid voltage drops and ensure low impedance connections.

 

[mmckenna]

This is bonding, not grounding questions.
I have read thru;
ARRL General Class License Manual Chapter 5.5
ARRL Handbook Volume 5 Chapter 22.1.8
publications on RF bonding and I have a few questions on what should be bonded and what doesn't have to be.

I don't have answers for all these, but I can add a few comments. Not sure where ARRL gets it's info, but there's some good documents out there if you look at the Motorola R56, or a PSAP design guide. The R56/PSAP stuff will likely go way beyond what hams would do, and probably way outside the budget for most.

Do these have to be bonded?;
1. Electrical electronic equipment in non-metallic (plastic) enclosures,

I don't know how you'd bond the case if it isn't designed for it. If it's making noise, wrapping it in EMI/RFI tape and bonding that would be a place to start.

2. PC related, monitors, printers, copiers, Laptops (other than Towers in a metal enclosure),
3. Network equipment; Routers, VOIP adapters, Switches etc,

I ground the **** out of our stuff at work if it's in my space. Our network guys tend to rely on the power cord, or grounding through the rack mount. A lot of the higher end big name stuff (non-consumer) will have a grounding point on them and often come with a suitable lug in the box. If I see a grounding stud on -any- piece of equipment, I figure the designer/manufacturer has put it there for a reason. I don't like relying on rack mounting ears/screws as the ground, and a long ground lead back to the panel using the power cord isn't ideal. Usually anything telecom/radio related will get bonded so everything is at equal potential in the event of a lightning event, and so any stray noise has an easy path to earth.

4. Equipment in metal enclosures that are DC powered thru a DC wall adapter, CCTV DVR,

If it's giving you noise, a good place to start would be grounding it. In a radio/telco application or at a radio site, it'd ground it.

5. Scanner receivers connected to a grounded roof antenna,

Most probably wouldn't. If I was building out a really good station and all the equipment was bonded, I'd probably take the extra step of grounding the radio chassis. Overkill? Maybe, but probably not going to hurt.

6. Test equipment in plastic enclosures with earth ground; Spectrum Analyzers, Scopes, etc,

See above, if the manufacturer took the time to put a grounding point on it, then they probably want it grounded.

7. Metal file cabinets or desks (non metal top, metal drawers),

That's probably going too far, unless you had a really good reason.

8. Telephones, lamps with metal bases, metal enclosed Bench Power Supplies,

Telephone circuit would pass through an entrance protector at your home, so it should be OK. Lamp, probably not. Power supply, I probably would make sure it had a grounded power cord at minimum.

9. Lastly a Dual band 50w (almost always set for 5w out) mobile and/or a metal case PS.

I think in a good installation, all the radios should be bonded.

All of this is in a 2nd floor room in a 'double' home with a #6 gauge ground wire tied to the electrical ground via two 8' ground rods. The AC outlet is grounded where everything gets run to thru power strips.

I know 2nd floor rooms can be a challenge to get a good RF ground, so it sounds like you are on the right track.

I'd never rely on the electrical outlet ground for anything other than an electrical safety ground. It takes a long path back to the panel, where it gets connected in with the neutral and all the other stuff in the house.

You'll probably get a lot of good opinions on this, and some that probably don't jive with what I've said. If you look at R56, that'll give you some good info. If you really want to go nuts with grounding, take a look at the Bell System standards for their microwave sites. Some of those were designed specifically for EMP/nuclear blast survivability, and they do some really amazing work. They may have gone as far as to bond desks and file cabinets….

 

[videobruce]

I kinda question some of the ARRL's text.

RF noise from other equipment isn't a issue (at least not yet, no HF gear yet).
Other than the PC 'Tower', none of the items listed have anywhere to even try to attaching a bonding cable including the Monitor and Router!
The test equipment has no additional ground provisions.
The telephone is thru VoIP, twister pair/copper is long gone here.

Regarding the transceivers with external PS's, can I assume BOTH the radio and the PS be bonded together then connected to the #6 ground buss??


That R56/PSAP stuff is way overkill for my situation.

 

[mmckenna]

I kinda question some of the ARRL's text.

I'm sure the ARRL means well, and most of their recommendations are probably rooted in good design. Problem I've found in the past is some hams will tend to try and over engineer everything as some sort of 'one up-man-ship' between each other. Sometimes it gets out of hand.

Regarding the transceivers with external PS's, can I assume BOTH the radio and the PS be bonded together then connected to the #6 ground buss??

I would. The radios often have the negative power lead bonded to the radio chassis. Power supplies usually don't. I'd think that having both the radio and ps chassis bonded to ground would be a good idea.

That R56/PSAP stuff is way overkill for my situation.

For hobby use, I 100% agree.
I'd say make sure you meet the National Electric Code at minimum, and make sure your major components are bonded to ground. But grounding monitors and telephones really sounds like someone at ARRL has gone a bit extreme.

 

[videobruce]

Telephones were not mentioned, but monitors were.

 

[serial14]

@mmckenna do you have any sense of benefit / impact you get from grounding Networking / IT equipment? Same question for bonding radio bodies when they are rack mounted.

Professionally I've worked in IT situations where things just get racked with no further thought. I've also worked in situations where the regulations said that networking gear needs to be bonded with a ground wire in the rack to a common grounding rail and this gets inspected. But I've never been in a situation where I could analyze both approaches to appreciate the benefit.

I admit at home I have scanners, networking, and IT stuff all in the same rack, yet take the lazy approach of just racking it. I'm curious if it could be better if I took the time to explicitly ground/bond all the equipment. It would make sense in my situation there is some benefit to be had.

 

[mmckenna]

@mmckenna do you have any sense of benefit / impact you get from grounding Networking / IT equipment? Same question for bonding radio bodies when they are rack mounted.

I have no conclusive data/comparisons on the networking side of this. I'm telecom (PBX/Radio).
"Back-in-the-day" when all our phones were either analog or TDM wired, grounding was critical. Long wires running all over the place, miles long loop length, different buildings with different ground potentials and a ton of other variables made it important on the telephone side. Early on, when I was getting started, our analog phones used a button that temporarily grounded one side of the circuit to signal the PBX similar to hook flash, that relied on good grounds.

On the network side, it was recommended by companies like Cisco and Brocade. Our installation standards for all the wiring closets required a master telecom ground bar, and all equipment was to be bonded to that. Most equipment is, but not 100%.

On the phone side, I've kept that up, as while we are mostly VoIP, we still maintain a lot of analog circuits. In reality, it's not hard to do it, and preventing issues is the ultimate goal. While it's not always common on the IP side, 5 Nine's is still our goal on the telecom side. Since our reliance on IP is always growing, I try to make sure any networking equipment we directly touch is properly grounded per all the BICSI, NEC and industry standards.

Relying on grounding through the rack ears probably works fine, but it really depends on the installer, if the rack itself is properly grounded, electrical grounds, etc. I prefer to not leave things up to chance, especially when failures reflect directly on us.

Professionally I've worked in IT situations where things just get racked with no further thought. I've also worked in situations where the regulations said that networking gear needs to be bonded with a ground wire in the rack to a common grounding rail and this gets inspected. But I've never been in a situation where I could analyze both approaches to appreciate the benefit.

The only actual incidents I can recall go way, way back to the days when we still ran a lot of terminal servers and slow speed wired terminal connections ran over unground copper cables. Some networking engineer decided that proper grounding was optional and only had entrance protectors on one side of the circuits. A lightning strike induced enough energy into the underground copper plant to damage a lot of equipment. Unfortunately, they still didn't learn. It wasn't until we hired an ex-Bell System Outside Plant Engineer that it was all finally done right.

With so much of the interconnections now handled over fiber, the need for the grounding might be reduced, but I still feel better seeing things properly bonded to ground, and not relying on the electrical safety ground, rack screws, or other questionable means of grounding.

I like the idea of low impedance paths to main building ground busses, and not relying on a long ground run through metal conduit, electrical panels to get back where it want's to go.

I admit at home I have scanners, networking, and IT stuff all in the same rack, yet take the lazy approach of just racking it. I'm curious if it could be better if I took the time to explicitly ground/bond all the equipment. It would make sense in my situation there is some benefit to be had.

Seems to vary for hobbyists. Most don't seem to do it, and are fine. I prefer to do it myself as that's part of the challenge. I try to look at things as a large system of interconnected equipment.

 

[mmckenna]

@mmckenna do you have any sense of benefit / impact you get from grounding Networking / IT equipment? Same question for bonding radio bodies when they are rack mounted.

Remembered one instance, not really IP networking related, but more about the importance of grounding:

We had a mountain top site where the Incumbent Local Exchange Carrier delivered us a T-1 circuit via microwave. The T-1 linked nodes of our PBX together and allowed calling between sites. Worked very well, as Bell System always engineered their systems well.

Until one day it didn't. We were having sporadic outages on the T-1 and the Bell guys kept responding, but it was always running when they go there and would close out the ticket.
One day I was on the mountain and the T-1 dropped. I started testing things and found all kinds of stray voltages on the pairs. Started looking at their frame grounding, T-1 NI grounding and other stuff. Eventually found that some well meaning person had disconnected the main ground lead for the frame. At the time I was talking to the Bell ticketing people opening a ticket on the issue. I said "Hey, wait a second…". I tied the ground back down and everything restored. I had them put the ticket into observation state for 24 hours so we could all watch it. T-1 never dropped again(*).

* "never dropped again" until a well meaning data network guy on our side started messing with our shared CSU trying to "fix" an issue they were having on their network channels, without understanding how T-1 clocking works. But that's another rant….

 

[K3YGX]

Retired phone tech here.
When we mounted telco station protection, it was always grounded there. (or supposed to be).
Station wiring was not - just 'tip and ring' (red and green, or white/blue)