buzzlectric
Member
- Location
- Iowa
On a CNC,Injection Molding Machine, do all ground conductors have to go to the same lug on the machine or can you just attach to the steel frame of the machine with the ground rod conductor?
ground rod conductor
- Thread starter buzzlectric
- Start date
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bphgravity
Senior Member
- Location
- Florida
Re: ground rod conductor
The first thing you need to do is follow the manufacturer's instructions if provided and available, otherwise, it should be acceptable to attach at any point on the frame.
The first thing you need to do is follow the manufacturer's instructions if provided and available, otherwise, it should be acceptable to attach at any point on the frame.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Re: ground rod conductor
for the purposes of safety, all the metal parts of the machine are bonded to the incoming equipment grounding conductor (EGC). normally the machinery maker will bond the metal parts together during fabrication/assembly using a variety of means. all you have to do is attach the incoming EGC to whatever point(s) they specify - usually this is a ground lug located either on the machine or in the control panel.
a ground rod local to the machine is not required for saftey purposes, nor does it serve any real safety purpose. If you decide to have one anyway, it should be bonded to the same lug as your incoming EGC (although really you can basically connect it anywhere as long as it is bonded to the machine somewhere).
it is a good idea to bond to the building steel in the area as well.
from a safety standpoint, you want to make sure that if you get a ground fault (i.e.-a hot wire touches an exposed metal part) the short circuit protection for that circuit (either a fuse or a CB) will open up to prevent you from being electrocuted.
having said all that, it is VERY important that you make sure that you do NOT connect the EGC or any other metal part to the incoming neutral, if there is one. This will result in a potentially dangerous condition and can create electrical noise as well that can negatively affect the equipment operation.
electrical noise reduction is another thing altogether. most times if you properly bond the machine for safety purposes, you will not have major noise issues.
for the purposes of safety, all the metal parts of the machine are bonded to the incoming equipment grounding conductor (EGC). normally the machinery maker will bond the metal parts together during fabrication/assembly using a variety of means. all you have to do is attach the incoming EGC to whatever point(s) they specify - usually this is a ground lug located either on the machine or in the control panel.
a ground rod local to the machine is not required for saftey purposes, nor does it serve any real safety purpose. If you decide to have one anyway, it should be bonded to the same lug as your incoming EGC (although really you can basically connect it anywhere as long as it is bonded to the machine somewhere).
it is a good idea to bond to the building steel in the area as well.
from a safety standpoint, you want to make sure that if you get a ground fault (i.e.-a hot wire touches an exposed metal part) the short circuit protection for that circuit (either a fuse or a CB) will open up to prevent you from being electrocuted.
having said all that, it is VERY important that you make sure that you do NOT connect the EGC or any other metal part to the incoming neutral, if there is one. This will result in a potentially dangerous condition and can create electrical noise as well that can negatively affect the equipment operation.
electrical noise reduction is another thing altogether. most times if you properly bond the machine for safety purposes, you will not have major noise issues.
jwelectric
Senior Member
- Location
- North Carolina
Re: ground rod conductor
I was asked this same question about four months ago while touring a plastic blow mold plant near my home. The maintenance department was rebuilding their machines. You do not have to use a bare #6 copper conductor at every junction box was the answer I gave then, could this be from the same place?
I was asked this same question about four months ago while touring a plastic blow mold plant near my home. The maintenance department was rebuilding their machines. You do not have to use a bare #6 copper conductor at every junction box was the answer I gave then, could this be from the same place?
buzzlectric
Member
- Location
- Iowa
Re: ground rod conductor
we are not bonding junction box's, just installing ground rods. We don't blow mold, so i doubt you have been here.
we are not bonding junction box's, just installing ground rods. We don't blow mold, so i doubt you have been here.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Re: ground rod conductor
careful with your answer. You almost certainly will elarn something from the responses to your answer.
Just out of curiousity, why are you installing ground rods?
careful with your answer. You almost certainly will elarn something from the responses to your answer.
bphgravity
Senior Member
- Location
- Florida
Re: ground rod conductor
If the manufacturer requires a ground rod, regardless of why they think they need one, wouldn't it be required to be installed?
Many of the generators I see being installed today are not connected as SDS's yet the manufacturer places a lug on the frame and calls for a ground rod.
If the manufacturer requires a ground rod, regardless of why they think they need one, wouldn't it be required to be installed?
Many of the generators I see being installed today are not connected as SDS's yet the manufacturer places a lug on the frame and calls for a ground rod.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Re: ground rod conductor
I wonder if they have a spec on earth resistance? or what to do if they don't make it with one rod? do they have to do two then? or three? is 25 ohms OK? if so why? what would the purpose of this ground rod be?
I agree that in general you should install things in accordance with the manufacturer's instructions. these questions are more curiousity than anythign else.
In this case it appears the plant is adding ground rods. it's not clear the manufacturer called for them, nor why they would.
I wonder if they have a spec on earth resistance? or what to do if they don't make it with one rod? do they have to do two then? or three? is 25 ohms OK? if so why? what would the purpose of this ground rod be?
I agree that in general you should install things in accordance with the manufacturer's instructions. these questions are more curiousity than anythign else.
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