The importance of checking Electrical connections 1/31/14
A.k.a. preventative maintenance.
The topic of preventative maintenance is one of great importance as it helps the property owner save money and time by getting the most life possible out of the equipment that makes up his facility; it also helps create a safer environment to do your work in. The P.M. process involves everything from electrical and mechanical to plumbing and structures and adopting a routine program is quite simple!
The element of regular electrical connection inspection is very near and dear to my heart! Having been an electrician of many sorts and a designer for most of my career I have learned the importance of this practice, sometimes the hard way!
I am going to begin the discussion with newly installed equipment i.e.: Electrical panels with lugs and circuit breakers— when conductors are installed into these components they are supposed to be tightened to a specific torque value, I am sure most of the time this occurs! However that is the last time that connection will be checked and maybe during its entire life span!
Note: Most things have give, so when a conductor is first tightened is gives but it may continue to give even after this first tightening (Just because of its own elasticity) so you now have a connection that will potentially become very loose! Also, it is worth noting that conductors may become loose because of expansion and contraction to heating and cooling- The rate of this process is often a result of the size of the load, the environment and the property of the conductor including an improperly tightened connection. I have found that with new connections I check them several times over the period of several days and am often amazed to find several connections needing attention.
Another important area to consider is vibrating equipment-compressors and HVAC equipment and contactors can institute mechanical vibrations that cause fittings and connections to come loose also causing conduits to come apart potentially affecting the grounding system!
Harmonic distortion can institute heat and vibration into the system as well creating or adding to loose connections! And since our loads this day and age are mostly comprised of non linear loads harmonics has snuck in the back door with the electronic age and has become a constant burden ass well!
So what does this all mean?
Let me start off with a few claims that I have heard for years from my customers. The most common is; "My electrical system is fine, its working as we speak we’ve never had much down time." With a local military entity--The truth was there were serious problems developing i.e.
Unmanageable noise in servers, computer inconveniences, nuisance tripping of circuit breakers which involved, at times, critical equipment! Motors burning up without explanation (At least to the untrained eye), Low power factor at our service and overall a disruption that slowed down our ability to do our jobs measured at times in many hours of lost time which equates to lost dollars too.
To illustrate how much trouble a single loose connection can cause, early in my career I was called to an aircraft hanger to assist an HVAC technician with getting power to a heater located on top of a mezzanine. As it turns out the panel thus breaker that supplied power to his unit (A 42 space 208/120 volt 200 amp apparatus) was located just ten feet away. The HVAC tech told me that everything was hooked but he was getting no power so I took a look inside the panel that was already open and was aghast at the scene!
The breaker which was right next to the main lugs that supplied power to his unit had become so loose that it had destroyed the buss it was bolted to (at least on its surface). There was a measurable gap between the foot (Connection point) of the breaker and what was left of the buss; there was corrosion up and down the buss which also showed that other breakers had become involved too! The heat was so intense that it had melted the insulation on the 90C conductors and had damaged the feeders supplying power to this unit, the panel was non-repairable! What if there had been a fire? This hanger housed a KC-135 Taker jet and lots of staff members.
I spent lots of time and money changing out this panel-board all because of a loose connection and it appeared that it all began with the HVAC circuit mixed with no preventative Maintenance! That was a relative easy fix compared to what it could have been if that panel had been mounted flush in a concrete or block wall—if it had been mounted in or to a wood framed wall a fire most likely would have already occurred.
It only takes a few seconds to evaluate a connection which can be done without removing panel covers by using IR/ultrasonic detectors, However I prefer at least every other time (Once you have begun a P.M. routine) Pulling the covers and doing a visual and physical inspection simply because the Hi tech equipment can’t take into account times of low or no loading-word to the wise!
In the end not inspecting your equipment for loose connections and or harmonic issues can cause you to face serious down time, destroyed equipment, IR losses and low power factor which the power company will fine you for (If it’s bad enough), injured employees and possibly a fire to one level or another.
Monetarily, you will be less happy!
Hope this helps,
Layne T. Oliver
Retired Lead Electrician
Utah National Guard
A.k.a. preventative maintenance.
The topic of preventative maintenance is one of great importance as it helps the property owner save money and time by getting the most life possible out of the equipment that makes up his facility; it also helps create a safer environment to do your work in. The P.M. process involves everything from electrical and mechanical to plumbing and structures and adopting a routine program is quite simple!
The element of regular electrical connection inspection is very near and dear to my heart! Having been an electrician of many sorts and a designer for most of my career I have learned the importance of this practice, sometimes the hard way!
I am going to begin the discussion with newly installed equipment i.e.: Electrical panels with lugs and circuit breakers— when conductors are installed into these components they are supposed to be tightened to a specific torque value, I am sure most of the time this occurs! However that is the last time that connection will be checked and maybe during its entire life span!
Note: Most things have give, so when a conductor is first tightened is gives but it may continue to give even after this first tightening (Just because of its own elasticity) so you now have a connection that will potentially become very loose! Also, it is worth noting that conductors may become loose because of expansion and contraction to heating and cooling- The rate of this process is often a result of the size of the load, the environment and the property of the conductor including an improperly tightened connection. I have found that with new connections I check them several times over the period of several days and am often amazed to find several connections needing attention.
Another important area to consider is vibrating equipment-compressors and HVAC equipment and contactors can institute mechanical vibrations that cause fittings and connections to come loose also causing conduits to come apart potentially affecting the grounding system!
Harmonic distortion can institute heat and vibration into the system as well creating or adding to loose connections! And since our loads this day and age are mostly comprised of non linear loads harmonics has snuck in the back door with the electronic age and has become a constant burden ass well!
So what does this all mean?
Let me start off with a few claims that I have heard for years from my customers. The most common is; "My electrical system is fine, its working as we speak we’ve never had much down time." With a local military entity--The truth was there were serious problems developing i.e.
Unmanageable noise in servers, computer inconveniences, nuisance tripping of circuit breakers which involved, at times, critical equipment! Motors burning up without explanation (At least to the untrained eye), Low power factor at our service and overall a disruption that slowed down our ability to do our jobs measured at times in many hours of lost time which equates to lost dollars too.
To illustrate how much trouble a single loose connection can cause, early in my career I was called to an aircraft hanger to assist an HVAC technician with getting power to a heater located on top of a mezzanine. As it turns out the panel thus breaker that supplied power to his unit (A 42 space 208/120 volt 200 amp apparatus) was located just ten feet away. The HVAC tech told me that everything was hooked but he was getting no power so I took a look inside the panel that was already open and was aghast at the scene!
The breaker which was right next to the main lugs that supplied power to his unit had become so loose that it had destroyed the buss it was bolted to (at least on its surface). There was a measurable gap between the foot (Connection point) of the breaker and what was left of the buss; there was corrosion up and down the buss which also showed that other breakers had become involved too! The heat was so intense that it had melted the insulation on the 90C conductors and had damaged the feeders supplying power to this unit, the panel was non-repairable! What if there had been a fire? This hanger housed a KC-135 Taker jet and lots of staff members.
I spent lots of time and money changing out this panel-board all because of a loose connection and it appeared that it all began with the HVAC circuit mixed with no preventative Maintenance! That was a relative easy fix compared to what it could have been if that panel had been mounted flush in a concrete or block wall—if it had been mounted in or to a wood framed wall a fire most likely would have already occurred.
It only takes a few seconds to evaluate a connection which can be done without removing panel covers by using IR/ultrasonic detectors, However I prefer at least every other time (Once you have begun a P.M. routine) Pulling the covers and doing a visual and physical inspection simply because the Hi tech equipment can’t take into account times of low or no loading-word to the wise!
In the end not inspecting your equipment for loose connections and or harmonic issues can cause you to face serious down time, destroyed equipment, IR losses and low power factor which the power company will fine you for (If it’s bad enough), injured employees and possibly a fire to one level or another.
Monetarily, you will be less happy!
Hope this helps,
Layne T. Oliver
Retired Lead Electrician
Utah National Guard