Nace CP 1 - Crossectional Area

Basic Electricity 1:4
CP 1 – Cathodic Protection Tester Course Manual
© NACE International, 2000
02/01/05
L
R
A
ρ
L
R
A
ρ
Figure 1.1a Figure 1.1b
The terms are the same as in the above equation.
Resistance to current flow is lowest for:
• Low-resistivity (high-conductivity) media
• Short length for current flow
• Large area of current flow
Resistance will be greatest for:
• High-resistivity (low-conductivity) media
• Long path length for current flow
• Small cross-sectional area of current flow
Crossectional Area
A(cm
2
) = h x w
where: h = height (cm)
w = width (cm)
A(cm
2
) = πr
2
where: r = radius (cm)