Table 1. Characteristic variables and pylon structure and line recorded for each pylon and line reviewed (for more details see Supporting information).

Structural Variable		Description	N
Function	Holder	Pylons that support the conductors	4727
	Anchor	Pylons that employ horizontal structures to generate cable tension	812
	Special	Pylons that have a special function, such as line intersections, cut-outs, transformers, etc.	765
Model	Flat	All phases are at the same level	2355
	Cross-shaped	Central phase above lateral phase	1475
	Vault	Central phase above lateral phase, always with suspended insulators	2097
	Lattice vault	Central phase above lateral phase, always with suspended insulators, wider than vaults	198
	Three levels	Each phase at one different level	179
Insulators	0	Pin-type insulators	2506
	2–9	Number of insulators at each phase	-
Phases over the crossarm	0,1 or 3	Number of phases over the crossarm	-
Tower	Steel	Tower composition material	3990
	Concrete		2314
Crossarm	Steel	Crossarm composition material	6231
	Concrete		73
Mitigation measures	None	No mitigation measure	5597
	Cable covers	Installation of rubber cable covers	442
	Silicone covers	Installation of silicone cable covers	77
	Insulator substitution	Changing ceramic insulators to glass ones	30
	Extension	Non-conductive steel extension used to elongate the length of the string of insulators in anchor or special pylons	158