difference b/w ht nd lt pannels

very interesting question.!!! you can expect loads of answer.As I believe You intensionally wrote this stupidity in electrical engineering forum. I understand From your question:-

you need to know :

1.voltage

2.ht

3.lt

4.cables

Anything below 1000AC is normally considered "lt".

Insulation, HT has more of it!

Voltage:

ht = Higher

lt = Lower

Cables:

ht = Thicker insulation (as Tony said)

lt = Thinner insulation

Major difference;

ht = more expensive

lt = less expensive

HT = High Tension, what we in North America call Medium Voltage (and above, apparently they don't differentiate the same way).

LT = Low Tension or what we call Low Voltage, meaning 600V (690V for them) and below.

The differences in "panels" as you call them are going to fall into 3 main categories, there are lots of nuances within these of course.

First and foremost is that any switching component must account for the longer arc length that is going to occur as voltage (tension) increases. So a Circuit Breaker for HT systems is going to be increasingly larger and more expensive than it's LT equivalent in terms of amps, because there needs to be more dielectric separation in order to extinguish the arc that forms when you break the circuit. Al alternative usually employed is to use sealed vacuum bottles and at higher voltages, inert gas sealed (such as SF6) tubes to house the components so that the arc distance does not get ridiculous.

Also, as the voltage goes up, the "creapage distance" must increase as well, the total surface area distance that must separate current carrying components to that ionized gasses and dust accumulation do not allow a flash-over between them. So the gear (panels) must by necessity get larger with increasing voltage.

Thirdly, the mechanical forces created during a fault by the magnetic fields around current carrying components is directly related to the total energy in the system. As voltage increases,even low amounts of current still contain very high levels of energy. So if equivalently sized (amperage) panels are compared, HT panels would need to be physically stronger than panels in LT systems.

Best reference source is usually the IEC (www.iec.ch). See IEC60038:1983 for standard voltages. Anything below 1000V AC (1500V DC) is defined as low voltage, above it is high voltage - LV/HV = LT/HT in some regions.

Biggest difference in panels ("assemblies" as per the standards) will be the clearance distances between live parts and/or the associated insulation etc.

when it comes to panels, space clearance between Ph-Ph or Ph-E differs. When it is a cable, insulation differs.